Struct UriBuf

pub struct UriBuf(/* private fields */);

Sized, heap-allocated string type guaranteed to contain a well-formed IETF-RFC3986 URI or network path.

The unsized counterpart is Uri.

This type implements std::ops::Deref<Uri>, so you can also use all of the methods from Uri on this type.

Implementations

impl UriBuf

Unsafe Methods

UriBuf needs some unsafe methods in order to function properly. This section is where they are all located.

pub unsafe fn from_string_unchecked(s: String) -> UriBuf

Unchecked version of UriBuf::from_string.

Safety

This method is marked as unsafe because it allows you to construct a UriBuf with a value that is not a well-formed URI reference.

impl UriBuf

pub fn new<Sch, Hos, Pat, Que, Frg>( scheme: Sch, host: Hos, port: Option<u16>, path: Pat, query: Option<Que>, fragment: Option<Frg>, ) -> UriBuf

where Sch: Into<String>, Hos: AsRef<str>, Pat: AsRef<str>, Que: AsRef<str>, Frg: AsRef<str>,

Creates a new UriBuf from unescaped component values.

pub fn from_scheme_authority<Sch, Aut>(scheme: Sch, authority: Aut) -> UriBuf

where Sch: Into<String>, Aut: AsRef<str>,

Constructs a UriBuf from a scheme and authority.

The authority should not be percent encoded. If the given scheme contains invalid characters, this method will panic.

Example

use async_coap_uri::prelude::*;
let authority = "user@[2001:0db8:85a3::1%en2]:8080";

let uri_buf = UriBuf::from_scheme_authority("http", authority);

assert_eq!(uri_buf, uri!("http://user@[2001:0db8:85a3::1%25en2]:8080"));

pub fn from_host_rel_ref<Hos, RR>(host: Hos, rel_ref: RR) -> UriBuf

where Hos: AsRef<str>, RR: AsRef<RelRef>,

Constructs a network path from a host and a relative reference.

Example

use async_coap_uri::prelude::*;
let host = "example.com";
let rel_ref = rel_ref!("./foobar?q");

let uri_buf = UriBuf::from_host_rel_ref(host, rel_ref);

assert_eq!(uri_buf, uri!("//example.com/foobar?q"));

pub fn from_scheme_host_port<Sch, Hos>( scheme: Sch, host: Hos, port: Option<u16>, ) -> UriBuf

where Sch: Into<String>, Hos: AsRef<str>,

Constructs a UriBuf from a scheme, host and an optional port number.

The host should not be percent encoded. If the given scheme contains invalid characters, this method will panic.

pub fn from_str<S: AsRef<str>>(s: S) -> Result<UriBuf, ParseError>

Attempts to create a new UriBuf from a string slice.

pub fn from_string(s: String) -> Result<UriBuf, ParseError>

Attempts to create a new UriBuf from a String.

pub fn from_uri<S: AsRef<UriRef>>(s: S) -> Option<UriBuf>

Attempts to create a new UriBuf from a UriRef slice.

impl UriBuf

pub fn as_uri(&self) -> &Uri

Borrows a Uri slice containing this URI.

impl UriBuf

Manipulation

pub fn resolve<T: AnyUriRef + ?Sized>( &mut self, dest: &T, ) -> Result<(), ResolveError>

Using this URI as the base, performs “relative resolution” to the given instance implementing AnyUriRef, updating the content of this UriBuf with the result.

pub fn replace_path(&mut self, rel: &RelRef)

Replaces the path, query, and fragment with that from rel.

impl UriBuf

Methods inherited from UriRefBuf

pub fn as_str(&self) -> &str

Returns a string slice for this instance.

pub unsafe fn as_mut_str(&mut self) -> &mut str

Returns a mutable string slice (&mut str) for this instance.

Safety

This method is not safe because this type makes guarantees about the structure of the content it contains, which may be violated by using this method.

pub fn as_mut_uri_ref(&mut self) -> &mut UriRef

Borrows a reference to this mutable instance as a mutable URI-Reference (&mut UriRef).

pub fn truncate_heir_part(&mut self)

Removes the authority, path, query, and fragment components, if present.

pub fn truncate_path(&mut self)

Removes the path, query, and fragment components, if present.

pub fn truncate_query(&mut self)

Removes the query, and fragment components, if present.

pub fn truncate_fragment(&mut self)

Removes fragment component, if present.

pub fn truncate_resource(&mut self)

Removes the last path component (up to, but not including, the last slash), along with the query and fragment components, if present.

See UriRefBuf::truncate_resource for more information.

pub fn truncate_last_path_segment(&mut self)

Removes the last path item, along with the query and fragment components, if present.

See UriRefBuf::truncate_last_path_segment for more information.

pub fn add_trailing_slash(&mut self) -> bool

Adds a trailing slash to the path if there isn’t a trailing slash already present.

pub fn add_leading_slash(&mut self) -> bool

Adds a leading slash to the path if there isn’t one already present.

pub fn push_path_segment(&mut self, segment: &str, trailing_slash: bool)

Percent-encodes and appends the given path segment to this instance, truncating any existing query or fragment in the process.

If this instance isn’t empty and doesn’t end with a slash, one is first added. A trailing slash will be appended depending on the value of the trailing_slash argument.

pub fn push_query_item(&mut self, item: &str)

Percent-encodes and appends the given query item to this instance, truncating any existing fragment in the process.

If no query is present, the query item is preceded with a ‘?’ to indicate the start of the query component. Otherwise, this method uses & to separate query items.

This method follows the common convention where spaces are encoded as + characters instead of %20.

pub fn push_query_key_value(&mut self, key: &str, value: &str)

Percent-encodes and appends the given query key/value pair to this URI-reference, truncating any existing fragment in the process.

If no query is present, the query item is preceded with a ‘?’ to indicate the start of the query component. Otherwise, this method uses & to separate query items.

This method follows the common convention where spaces are encoded as + characters instead of %20.

Methods from Deref<Target = Uri>

pub fn as_uri_ref(&self) -> &UriRef

Reinterpret this &Uri as a &UriRef.

pub fn to_uri_buf(&self) -> UriBuf

Copy the content of this &Uri into a new UriBuf and return it.

pub fn split(&self) -> (&Uri, &RelRef)

Splits this URI into the base and relative portions.

pub fn trim_fragment(&self) -> &Uri

Returns this URI without a fragment.

Examples

use async_coap_uri::prelude::*;
assert_eq!(uri!("http://a/#frag").trim_fragment(),  uri!("http://a/"));
assert_eq!(uri!("//a/b/c?blah#frag").trim_fragment(), uri!("//a/b/c?blah"));

pub fn trim_query(&self) -> &Uri

Returns this URI without a query or fragment.

Examples

use async_coap_uri::prelude::*;
assert_eq!(uri!("//foo/?bar").trim_query(),      uri!("//foo/"));
assert_eq!(uri!("http://a/#frag").trim_query(),  uri!("http://a/"));

pub fn trim_path(&self) -> &Uri

Returns this URI without a path, query, or fragment.

Examples

use async_coap_uri::prelude::*;
assert_eq!(uri!("//foo/?bar").trim_path(),      uri!("//foo"));
assert_eq!(uri!("http://a/#frag").trim_path(),  uri!("http://a"));

pub fn trim_resource(&self) -> &Uri

Returns this URI without the trailing part of the path that would be removed during relative-reference resolution.

Examples

use async_coap_uri::prelude::*;
assert_eq!(uri!("//foo/?bar").trim_resource(),      uri!("//foo/"));
assert_eq!(uri!("http://a/#frag").trim_resource(),  uri!("http://a/"));

Methods from Deref<Target = UriRef>

pub fn as_str(&self) -> &str

Returns this URI-reference as a string slice.

pub fn as_uri(&self) -> Option<&Uri>

Attempts to interpret this &UriRef as a &Uri, returning None if this UriRef doesn’t contain a proper URI.

pub fn as_rel_ref(&self) -> Option<&RelRef>

Attempts to interpret this &UriRef as a &RelRef, returning None if this UriRef doesn’t contain a relative-reference.

pub fn heir_part_start(&self) -> usize

Returns the index to the start of heir-part, as defined in IETF-RFC3986.

pub fn path_start(&self) -> usize

Returns the index to the first character in the path. Will return len() if there is no path, query, or fragment. If the return value is zero, then self is guaranteed to be a relative reference.

Examples

use async_coap_uri::prelude::*;
assert_eq!(uri_ref!("a").path_start(),               0);
assert_eq!(uri_ref!("a/b/c?blah#frag").path_start(), 0);
assert_eq!(uri_ref!("/a").path_start(),              0);
assert_eq!(uri_ref!("//foo/?bar").path_start(),      5);
assert_eq!(uri_ref!("http://a/#frag").path_start(),  8);
assert_eq!(uri_ref!("http://a").path_start(),  8);

pub fn path_end(&self) -> usize

Returns the index of the end of the path

pub fn query_start(&self) -> Option<usize>

Returns the index of the start of the query, including the ?. If there is no query, returns None.

pub fn fragment_start(&self) -> Option<usize>

Returns the index of the start of the fragment, including the #. If there is no fragment, returns None.

pub fn authority_range(&self) -> Option<Range<usize>>

Returns the byte index range that contains the authority, if present.

pub fn split(&self) -> (Option<&Uri>, &RelRef)

Splits this URI into the base and relative portions.

pub fn base(&self) -> Option<&Uri>

Returns the subset of this URI that contains the scheme and authority, without the path, query, or fragment. If this is possible, the result is a &Uri.

pub fn rel(&self) -> &RelRef

Returns this URI as a &RelRef, including only the path, query, and fragment. If this URI is already relative, this method simply returns the given URI unchanged.

pub fn scheme(&self) -> Option<&str>

Returns the scheme of this URI, if it has a scheme. The returned string can be used directly and does not need to be unescaped or percent-decoded.

pub fn raw_authority(&self) -> Option<&str>

Returns the percent-encoded authority part of this URI, if it has one.

The unescaped version of this method is UriRef::authority.

In general, this value should not be used directly. Most users will find the method raw_userinfo_host_port to be a more useful extraction.

See StrExt for more details on unescaping.

pub fn authority(&self) -> Option<Cow<'_, str>>

Percent-decoded version of UriRef::raw_authority, using std::borrow::Cow<str> instead of &str.

pub fn raw_userinfo_host_port( &self, ) -> Option<(Option<&str>, &str, Option<u16>)>

Returns a tuple containing the raw userinfo, raw host, and port number from the authority component.

The percent-decoded version of this method is UriRef::userinfo_host_port.

The userinfo and host should be unescaped before being used. See StrExt for more details.

pub fn userinfo_host_port( &self, ) -> Option<(Option<Cow<'_, str>>, Cow<'_, str>, Option<u16>)>

Percent-decoded version of UriRef::raw_userinfo_host_port, where the unescaped parts are represented as std::borrow::Cow<str> instances.

pub fn host(&self) -> Option<Cow<'_, str>>

Percent-decoded host as a std::borrow::Cow<str>, if present.

pub fn raw_path(&self) -> &str

Returns a string slice containing the raw, percent-encoded value of the path.

There is no unescaped version of this method because the resulting ambiguity of percent-encoded slashes (/) present a security risk. Use path_segments if you need an escaped version.

If you absolutely must, you can use the following code to obtain a lossy, percent-decoded version of the path that doesn’t decode %2F into slash characters:

let path = uri_ref!("%2F../a/%23/")
    .raw_path()
    .unescape_uri()
    .skip_slashes()
    .to_string();

assert_eq!(path, "%2F../a/#/");

pub fn path_as_rel_ref(&self) -> &RelRef

Returns the subset of this URI that is a path, without the scheme, authority, query, or fragment. Since this is itself a valid relative URI, it returns a &RelRef.

pub fn path_query_as_rel_ref(&self) -> &RelRef

Returns the subset of this URI that is a path and query, without the scheme, authority, or fragment. Since this is itself a valid relative URI, it returns a &RelRef.

pub fn raw_path_segments(&self) -> impl Iterator<Item = &str>

An iterator which returns each individual raw, percent-encoded path segment.

The percent-decoded (unescaped) version of this method is UriRef::path_segments.

The values returned by this iterator should be unescaped before being used. See StrExt and StrExt::unescape_uri for more details.

Example

use async_coap_uri::prelude::*;
let rel_ref = uri_ref!("g:a/%2F/bl%c3%a5b%c3%a6r");
let mut iter = rel_ref.raw_path_segments();

assert_eq!(iter.next(), Some("a"));
assert_eq!(iter.next(), Some("%2F"));
assert_eq!(iter.next(), Some("bl%c3%a5b%c3%a6r"));
assert_eq!(iter.next(), None);

pub fn path_segments(&self) -> impl Iterator<Item = Cow<'_, str>>

Percent-decoded (unescaped) version of UriRef::raw_path_segments, using std::borrow::Cow<str> instead of &str.

Example

use async_coap_uri::prelude::*;
use std::borrow::Cow;
let uri_ref = uri_ref!("g:a/%2F/bl%c3%a5b%c3%a6r");
let mut iter = uri_ref.path_segments();

assert_eq!(iter.next(), Some(Cow::from("a")));
assert_eq!(iter.next(), Some(Cow::from("/")));
assert_eq!(iter.next(), Some(Cow::from("blåbær")));
assert_eq!(iter.next(), None);

pub fn query_fragment_as_rel_ref(&self) -> Option<&RelRef>

Returns the subset of this URI that is the query and fragment, without the scheme, authority, or path. This method includes the ? prefix, making it a valid relative URI.

pub fn query_as_rel_ref(&self) -> Option<&RelRef>

Returns the subset of this URI that is the query, without the scheme, authority, path, or fragment. This method includes the ? prefix, making it a valid relative URI.

pub fn raw_query(&self) -> Option<&str>

Returns the escaped slice of the URI that contains the “query”, if present.

There is no unescaped version of this method because the resulting ambiguity of percent-encoded ampersands (&) and semicolons (;) present a security risk. Use query_items or query_key_values if you need a percent-decoded version.

pub fn raw_query_items(&self) -> impl Iterator<Item = &str>

Returns an iterator that iterates over all of the query items.

Both ; and & are acceptable query item delimiters.

The percent-decoded version of this method is UriRef::query_items.

The values returned by this iterator should be unescaped before being used. See StrExt and StrExt::unescape_uri for more details.

Example

use async_coap_uri::prelude::*;
let uri_ref = uri_ref!("/a/b/c?q=this:is&q=fun&q=bl%c3%a5b%c3%a6rsyltet%c3%b8y");
let mut iter = uri_ref.raw_query_items();

assert_eq!(iter.next(), Some("q=this:is"));
assert_eq!(iter.next(), Some("q=fun"));
assert_eq!(iter.next(), Some("q=bl%c3%a5b%c3%a6rsyltet%c3%b8y"));
assert_eq!(iter.next(), None);

pub fn raw_query_key_values(&self) -> impl Iterator<Item = (&str, &str)>

Similar to raw_query_items(), but additionally separates the key from the value for each query item.

The percent-decoded version of this method is UriRef::query_key_values.

Both keys and values are in their raw, escaped form. If you want escaped values, consider query_key_values().

Example

use async_coap_uri::prelude::*;
let uri_ref = uri_ref!("/a/b/c?inc&a=ok&b=q=q&c=bl%c3%a5b%c3%a6r");
let mut iter = uri_ref.raw_query_key_values();

assert_eq!(iter.next(), Some(("inc", "")));
assert_eq!(iter.next(), Some(("a", "ok")));
assert_eq!(iter.next(), Some(("b", "q=q")));
assert_eq!(iter.next(), Some(("c", "bl%c3%a5b%c3%a6r")));
assert_eq!(iter.next(), None);

pub fn query_items(&self) -> impl Iterator<Item = Cow<'_, str>>

Percent-decoded version of UriRef::raw_query_items, using std::borrow::Cow<str> instead of &str.

pub fn query_key_values( &self, ) -> impl Iterator<Item = (Cow<'_, str>, Cow<'_, str>)>

Similar to query_items(), but additionally separates the key from the value for each query item.

Both keys and values are percent-decoded and ready-to-use. If you want them in their raw, percent-encoded in form, use raw_query_key_values().

This method uses the Copy-on-write type (std::borrow::Cow) to avoid unnecessary memory allocations.

Example

use async_coap_uri::prelude::*;
use std::borrow::Cow;
let uri_ref = uri_ref!("/a/b/c?inc&a=ok&b=q=q&c=bl%c3%a5b%c3%a6r");
let mut iter = uri_ref.query_key_values();

assert_eq!(iter.next(), Some((Cow::from("inc"), Cow::from(""))));
assert_eq!(iter.next(), Some((Cow::from("a"), Cow::from("ok"))));
assert_eq!(iter.next(), Some((Cow::from("b"), Cow::from("q=q"))));
assert_eq!(iter.next(), Some((Cow::from("c"), Cow::from("blåbær"))));
assert_eq!(iter.next(), None);

pub fn fragment_as_rel_ref(&self) -> Option<&RelRef>

Returns the subset of this URI that is the query, without the scheme, authority, path, or query. This method includes the # prefix, making it a valid relative URI.

pub fn raw_fragment(&self) -> Option<&str>

Returns a string slice containing the fragment, if any.

The percent-decoded version of this method is UriRef::fragment.

This value should be unescaped before being used. See StrExt for more details.

pub fn fragment(&self) -> Option<Cow<'_, str>>

Percent-decoded version of UriRef::raw_fragment, using std::borrow::Cow<str> instead of &str.

pub fn has_trailing_slash(&self) -> bool

Returns true if the path has a trailing slash.

Examples

use async_coap_uri::prelude::*;
assert!(uri_ref!("http://a/").has_trailing_slash());
assert!(uri_ref!("/a/").has_trailing_slash());
assert!(uri_ref!("a/").has_trailing_slash());
assert!(uri_ref!("http://a/?q=foo").has_trailing_slash());

assert!(!uri_ref!("http://a").has_trailing_slash());
assert!(!uri_ref!("a/b").has_trailing_slash());
assert!(!uri_ref!("").has_trailing_slash());

pub fn trim_fragment(&self) -> &UriRef

Returns this URI-reference without a fragment.

Examples

use async_coap_uri::prelude::*;
assert_eq!(uri_ref!("http://a/#frag").trim_fragment(),  uri_ref!("http://a/"));
assert_eq!(uri_ref!("a/b/c?blah#frag").trim_fragment(), uri_ref!("a/b/c?blah"));

pub fn trim_query(&self) -> &UriRef

Returns this URI without a query or fragment.

Examples

use async_coap_uri::prelude::*;
assert_eq!(uri_ref!("//foo/?bar").trim_query(),      uri_ref!("//foo/"));
assert_eq!(uri_ref!("a/b/c?blah#frag").trim_query(), uri_ref!("a/b/c"));
assert_eq!(uri_ref!("http://a/#frag").trim_query(),  uri_ref!("http://a/"));

pub fn trim_path(&self) -> &UriRef

Returns this URI without a path, query, or fragment.

Examples

use async_coap_uri::prelude::*;
assert_eq!(uri_ref!("a/b/c?blah#frag").trim_path(), uri_ref!(""));
assert_eq!(uri_ref!("//foo/?bar").trim_path(),      uri_ref!("//foo"));
assert_eq!(uri_ref!("http://a/#frag").trim_path(),  uri_ref!("http://a"));

pub fn trim_heir_part(&self) -> &UriRef

Returns this URI without the “heir-part”, or anything thereafter.

Examples

use async_coap_uri::prelude::*;
assert_eq!(uri_ref!("a/b/c?blah#frag").trim_heir_part(), uri_ref!(""));
assert_eq!(uri_ref!("//foo/?bar").trim_heir_part(), uri_ref!(""));
assert_eq!(uri_ref!("http://a/#frag").trim_heir_part(), uri_ref!("http:"));

pub fn trim_resource(&self) -> &UriRef

Returns this URI without the trailing part of the path that would be removed during relative-reference resolution.

Examples

use async_coap_uri::prelude::*;
assert_eq!(uri_ref!("a").trim_resource(),               uri_ref!(""));
assert_eq!(uri_ref!("a/b/c?blah#frag").trim_resource(), uri_ref!("a/b/"));
assert_eq!(uri_ref!("/a").trim_resource(),              uri_ref!("/"));
assert_eq!(uri_ref!("//foo/?bar").trim_resource(),      uri_ref!("//foo/"));
assert_eq!(uri_ref!("http://a/#frag").trim_resource(),  uri_ref!("http://a/"));

pub fn trim_trailing_slash(&self) -> &UriRef

Removes any trailing slash that might be at the end of the path, along with the query and fragment.

If the path consists of a single slash (“/”), then it is not removed.

Examples

use async_coap_uri::prelude::*;
assert_eq!(uri_ref!("a").trim_trailing_slash(),                uri_ref!("a"));
assert_eq!(uri_ref!("a/b/c/?blah#frag").trim_trailing_slash(), uri_ref!("a/b/c"));
assert_eq!(uri_ref!("/").trim_trailing_slash(),                uri_ref!("/"));
assert_eq!(uri_ref!("//foo/?bar").trim_trailing_slash(),       uri_ref!("//foo/"));
assert_eq!(uri_ref!("http://a/#frag").trim_trailing_slash(),   uri_ref!("http://a/"));

Note that the uri-ref “//” (a network path with an empty authority and an empty path) does not get its trailing slash removed because it technically isn’t a part of the path. Likewise, the uri-ref “///” doesn’t get the last slash removed because this method won’t remove the first slash in the path. The uri-ref “////” however will have its trailing slash removed:

assert_eq!(uri_ref!("//").trim_trailing_slash(),    uri_ref!("//"));
assert_eq!(uri_ref!("///").trim_trailing_slash(),   uri_ref!("///"));
assert_eq!(uri_ref!("////").trim_trailing_slash(),  uri_ref!("///"));

pub fn trim_to_shorten(&self, base: &UriRef) -> Option<&RelRef>

Attempts to shorten this URI-reference given a base URI reference.

The returned reference can then be resolved using the base to recover the original URI reference.

use async_coap_uri::prelude::*;
let base = uri_ref!("http://example.com/a/b");
let target = uri_ref!("http://example.com/a/x/y/");

let shortened = target.trim_to_shorten(base).expect("Unable to shorten");
assert_eq!(shortened, rel_ref!("x/y/"));

let resolved = base.resolved(shortened).expect("Unable to resolve");
assert_eq!(resolved, target);

Methods from Deref<Target = str>

pub fn len(&self) -> usize

Returns the length of self.

This length is in bytes, not chars or graphemes. In other words, it might not be what a human considers the length of the string.

Examples

let len = "foo".len();
assert_eq!(3, len);

assert_eq!("ƒoo".len(), 4); // fancy f!
assert_eq!("ƒoo".chars().count(), 3);

pub fn is_empty(&self) -> bool

Returns true if self has a length of zero bytes.

Examples

let s = "";
assert!(s.is_empty());

let s = "not empty";
assert!(!s.is_empty());

pub fn is_char_boundary(&self, index: usize) -> bool

Checks that index-th byte is the first byte in a UTF-8 code point sequence or the end of the string.

The start and end of the string (when index == self.len()) are considered to be boundaries.

Returns false if index is greater than self.len().

Examples

let s = "Löwe 老虎 Léopard";
assert!(s.is_char_boundary(0));
// start of `老`
assert!(s.is_char_boundary(6));
assert!(s.is_char_boundary(s.len()));

// second byte of `ö`
assert!(!s.is_char_boundary(2));

// third byte of `老`
assert!(!s.is_char_boundary(8));

pub fn floor_char_boundary(&self, index: usize) -> usize

🔬This is a nightly-only experimental API. (round_char_boundary)

Finds the closest x not exceeding index where is_char_boundary(x) is true.

This method can help you truncate a string so that it’s still valid UTF-8, but doesn’t exceed a given number of bytes. Note that this is done purely at the character level and can still visually split graphemes, even though the underlying characters aren’t split. For example, the emoji 🧑‍🔬 (scientist) could be split so that the string only includes 🧑 (person) instead.

Examples

#![feature(round_char_boundary)]
let s = "❤️🧡💛💚💙💜";
assert_eq!(s.len(), 26);
assert!(!s.is_char_boundary(13));

let closest = s.floor_char_boundary(13);
assert_eq!(closest, 10);
assert_eq!(&s[..closest], "❤️🧡");

pub fn ceil_char_boundary(&self, index: usize) -> usize

🔬This is a nightly-only experimental API. (round_char_boundary)

Finds the closest x not below index where is_char_boundary(x) is true.

If index is greater than the length of the string, this returns the length of the string.

This method is the natural complement to floor_char_boundary. See that method for more details.

Examples

#![feature(round_char_boundary)]
let s = "❤️🧡💛💚💙💜";
assert_eq!(s.len(), 26);
assert!(!s.is_char_boundary(13));

let closest = s.ceil_char_boundary(13);
assert_eq!(closest, 14);
assert_eq!(&s[..closest], "❤️🧡💛");

pub fn as_bytes(&self) -> &[u8]

Converts a string slice to a byte slice. To convert the byte slice back into a string slice, use the from_utf8 function.

Examples

let bytes = "bors".as_bytes();
assert_eq!(b"bors", bytes);

pub fn as_ptr(&self) -> *const u8

Converts a string slice to a raw pointer.

As string slices are a slice of bytes, the raw pointer points to a u8. This pointer will be pointing to the first byte of the string slice.

The caller must ensure that the returned pointer is never written to. If you need to mutate the contents of the string slice, use as_mut_ptr.

Examples

let s = "Hello";
let ptr = s.as_ptr();

pub fn get<I>(&self, i: I) -> Option<&<I as SliceIndex<str>>::Output>

where I: SliceIndex<str>,

Returns a subslice of str.

This is the non-panicking alternative to indexing the str. Returns None whenever equivalent indexing operation would panic.

Examples

let v = String::from("🗻∈🌏");

assert_eq!(Some("🗻"), v.get(0..4));

// indices not on UTF-8 sequence boundaries
assert!(v.get(1..).is_none());
assert!(v.get(..8).is_none());

// out of bounds
assert!(v.get(..42).is_none());

pub unsafe fn get_unchecked<I>(&self, i: I) -> &<I as SliceIndex<str>>::Output

where I: SliceIndex<str>,

Returns an unchecked subslice of str.

This is the unchecked alternative to indexing the str.

Safety

Callers of this function are responsible that these preconditions are satisfied:

• The starting index must not exceed the ending index;
• Indexes must be within bounds of the original slice;
• Indexes must lie on UTF-8 sequence boundaries.

Failing that, the returned string slice may reference invalid memory or violate the invariants communicated by the str type.

Examples

let v = "🗻∈🌏";
unsafe {
    assert_eq!("🗻", v.get_unchecked(0..4));
    assert_eq!("∈", v.get_unchecked(4..7));
    assert_eq!("🌏", v.get_unchecked(7..11));
}

pub unsafe fn slice_unchecked(&self, begin: usize, end: usize) -> &str

👎Deprecated since 1.29.0: use get_unchecked(begin..end) instead

Creates a string slice from another string slice, bypassing safety checks.

This is generally not recommended, use with caution! For a safe alternative see str and Index.

This new slice goes from begin to end, including begin but excluding end.

To get a mutable string slice instead, see the slice_mut_unchecked method.

Safety

Callers of this function are responsible that three preconditions are satisfied:

• begin must not exceed end.
• begin and end must be byte positions within the string slice.
• begin and end must lie on UTF-8 sequence boundaries.

Examples

let s = "Löwe 老虎 Léopard";

unsafe {
    assert_eq!("Löwe 老虎 Léopard", s.slice_unchecked(0, 21));
}

let s = "Hello, world!";

unsafe {
    assert_eq!("world", s.slice_unchecked(7, 12));
}

pub fn split_at(&self, mid: usize) -> (&str, &str)

Divides one string slice into two at an index.

The argument, mid, should be a byte offset from the start of the string. It must also be on the boundary of a UTF-8 code point.

The two slices returned go from the start of the string slice to mid, and from mid to the end of the string slice.

To get mutable string slices instead, see the split_at_mut method.

Panics

Panics if mid is not on a UTF-8 code point boundary, or if it is past the end of the last code point of the string slice. For a non-panicking alternative see split_at_checked.

Examples

let s = "Per Martin-Löf";

let (first, last) = s.split_at(3);

assert_eq!("Per", first);
assert_eq!(" Martin-Löf", last);

pub fn split_at_checked(&self, mid: usize) -> Option<(&str, &str)>

Divides one string slice into two at an index.

The argument, mid, should be a valid byte offset from the start of the string. It must also be on the boundary of a UTF-8 code point. The method returns None if that’s not the case.

The two slices returned go from the start of the string slice to mid, and from mid to the end of the string slice.

To get mutable string slices instead, see the split_at_mut_checked method.

Examples

let s = "Per Martin-Löf";

let (first, last) = s.split_at_checked(3).unwrap();
assert_eq!("Per", first);
assert_eq!(" Martin-Löf", last);

assert_eq!(None, s.split_at_checked(13));  // Inside “ö”
assert_eq!(None, s.split_at_checked(16));  // Beyond the string length

pub fn chars(&self) -> Chars<'_>

Returns an iterator over the chars of a string slice.

As a string slice consists of valid UTF-8, we can iterate through a string slice by char. This method returns such an iterator.

It’s important to remember that char represents a Unicode Scalar Value, and might not match your idea of what a ‘character’ is. Iteration over grapheme clusters may be what you actually want. This functionality is not provided by Rust’s standard library, check crates.io instead.

Examples

Basic usage:

let word = "goodbye";

let count = word.chars().count();
assert_eq!(7, count);

let mut chars = word.chars();

assert_eq!(Some('g'), chars.next());
assert_eq!(Some('o'), chars.next());
assert_eq!(Some('o'), chars.next());
assert_eq!(Some('d'), chars.next());
assert_eq!(Some('b'), chars.next());
assert_eq!(Some('y'), chars.next());
assert_eq!(Some('e'), chars.next());

assert_eq!(None, chars.next());

Remember, chars might not match your intuition about characters:

let y = "y̆";

let mut chars = y.chars();

assert_eq!(Some('y'), chars.next()); // not 'y̆'
assert_eq!(Some('\u{0306}'), chars.next());

assert_eq!(None, chars.next());

pub fn char_indices(&self) -> CharIndices<'_>

Returns an iterator over the chars of a string slice, and their positions.

As a string slice consists of valid UTF-8, we can iterate through a string slice by char. This method returns an iterator of both these chars, as well as their byte positions.

The iterator yields tuples. The position is first, the char is second.

Examples

Basic usage:

let word = "goodbye";

let count = word.char_indices().count();
assert_eq!(7, count);

let mut char_indices = word.char_indices();

assert_eq!(Some((0, 'g')), char_indices.next());
assert_eq!(Some((1, 'o')), char_indices.next());
assert_eq!(Some((2, 'o')), char_indices.next());
assert_eq!(Some((3, 'd')), char_indices.next());
assert_eq!(Some((4, 'b')), char_indices.next());
assert_eq!(Some((5, 'y')), char_indices.next());
assert_eq!(Some((6, 'e')), char_indices.next());

assert_eq!(None, char_indices.next());

Remember, chars might not match your intuition about characters:

let yes = "y̆es";

let mut char_indices = yes.char_indices();

assert_eq!(Some((0, 'y')), char_indices.next()); // not (0, 'y̆')
assert_eq!(Some((1, '\u{0306}')), char_indices.next());

// note the 3 here - the previous character took up two bytes
assert_eq!(Some((3, 'e')), char_indices.next());
assert_eq!(Some((4, 's')), char_indices.next());

assert_eq!(None, char_indices.next());

pub fn bytes(&self) -> Bytes<'_>

Returns an iterator over the bytes of a string slice.

As a string slice consists of a sequence of bytes, we can iterate through a string slice by byte. This method returns such an iterator.

Examples

let mut bytes = "bors".bytes();

assert_eq!(Some(b'b'), bytes.next());
assert_eq!(Some(b'o'), bytes.next());
assert_eq!(Some(b'r'), bytes.next());
assert_eq!(Some(b's'), bytes.next());

assert_eq!(None, bytes.next());

pub fn split_whitespace(&self) -> SplitWhitespace<'_>

Splits a string slice by whitespace.

The iterator returned will return string slices that are sub-slices of the original string slice, separated by any amount of whitespace.

‘Whitespace’ is defined according to the terms of the Unicode Derived Core Property White_Space. If you only want to split on ASCII whitespace instead, use split_ascii_whitespace.

Examples

Basic usage:

let mut iter = "A few words".split_whitespace();

assert_eq!(Some("A"), iter.next());
assert_eq!(Some("few"), iter.next());
assert_eq!(Some("words"), iter.next());

assert_eq!(None, iter.next());

All kinds of whitespace are considered:

let mut iter = " Mary   had\ta\u{2009}little  \n\t lamb".split_whitespace();
assert_eq!(Some("Mary"), iter.next());
assert_eq!(Some("had"), iter.next());
assert_eq!(Some("a"), iter.next());
assert_eq!(Some("little"), iter.next());
assert_eq!(Some("lamb"), iter.next());

assert_eq!(None, iter.next());

If the string is empty or all whitespace, the iterator yields no string slices:

assert_eq!("".split_whitespace().next(), None);
assert_eq!("   ".split_whitespace().next(), None);

pub fn split_ascii_whitespace(&self) -> SplitAsciiWhitespace<'_>

Splits a string slice by ASCII whitespace.

The iterator returned will return string slices that are sub-slices of the original string slice, separated by any amount of ASCII whitespace.

This uses the same definition as char::is_ascii_whitespace. To split by Unicode Whitespace instead, use split_whitespace.

Examples

Basic usage:

let mut iter = "A few words".split_ascii_whitespace();

assert_eq!(Some("A"), iter.next());
assert_eq!(Some("few"), iter.next());
assert_eq!(Some("words"), iter.next());

assert_eq!(None, iter.next());

Various kinds of ASCII whitespace are considered (see char::is_ascii_whitespace):

let mut iter = " Mary   had\ta little  \n\t lamb".split_ascii_whitespace();
assert_eq!(Some("Mary"), iter.next());
assert_eq!(Some("had"), iter.next());
assert_eq!(Some("a"), iter.next());
assert_eq!(Some("little"), iter.next());
assert_eq!(Some("lamb"), iter.next());

assert_eq!(None, iter.next());

If the string is empty or all ASCII whitespace, the iterator yields no string slices:

assert_eq!("".split_ascii_whitespace().next(), None);
assert_eq!("   ".split_ascii_whitespace().next(), None);

pub fn lines(&self) -> Lines<'_>

Returns an iterator over the lines of a string, as string slices.

Lines are split at line endings that are either newlines (\n) or sequences of a carriage return followed by a line feed (\r\n).

Line terminators are not included in the lines returned by the iterator.

Note that any carriage return (\r) not immediately followed by a line feed (\n) does not split a line. These carriage returns are thereby included in the produced lines.

The final line ending is optional. A string that ends with a final line ending will return the same lines as an otherwise identical string without a final line ending.

Examples

Basic usage:

let text = "foo\r\nbar\n\nbaz\r";
let mut lines = text.lines();

assert_eq!(Some("foo"), lines.next());
assert_eq!(Some("bar"), lines.next());
assert_eq!(Some(""), lines.next());
// Trailing carriage return is included in the last line
assert_eq!(Some("baz\r"), lines.next());

assert_eq!(None, lines.next());

The final line does not require any ending:

let text = "foo\nbar\n\r\nbaz";
let mut lines = text.lines();

assert_eq!(Some("foo"), lines.next());
assert_eq!(Some("bar"), lines.next());
assert_eq!(Some(""), lines.next());
assert_eq!(Some("baz"), lines.next());

assert_eq!(None, lines.next());

pub fn lines_any(&self) -> LinesAny<'_>

👎Deprecated since 1.4.0: use lines() instead now

Returns an iterator over the lines of a string.

pub fn encode_utf16(&self) -> EncodeUtf16<'_>

Returns an iterator of u16 over the string encoded as native endian UTF-16 (without byte-order mark).

Examples

let text = "Zażółć gęślą jaźń";

let utf8_len = text.len();
let utf16_len = text.encode_utf16().count();

assert!(utf16_len <= utf8_len);

pub fn contains<P>(&self, pat: P) -> bool

where P: Pattern,

Returns true if the given pattern matches a sub-slice of this string slice.

Returns false if it does not.

The pattern can be a &str, char, a slice of chars, or a function or closure that determines if a character matches.

Examples

let bananas = "bananas";

assert!(bananas.contains("nana"));
assert!(!bananas.contains("apples"));

pub fn starts_with<P>(&self, pat: P) -> bool

where P: Pattern,

Returns true if the given pattern matches a prefix of this string slice.

Returns false if it does not.

The pattern can be a &str, in which case this function will return true if the &str is a prefix of this string slice.

The pattern can also be a char, a slice of chars, or a function or closure that determines if a character matches. These will only be checked against the first character of this string slice. Look at the second example below regarding behavior for slices of chars.

Examples

let bananas = "bananas";

assert!(bananas.starts_with("bana"));
assert!(!bananas.starts_with("nana"));

let bananas = "bananas";

// Note that both of these assert successfully.
assert!(bananas.starts_with(&['b', 'a', 'n', 'a']));
assert!(bananas.starts_with(&['a', 'b', 'c', 'd']));

pub fn ends_with<P>(&self, pat: P) -> bool

where P: Pattern, <P as Pattern>::Searcher<'a>: for<'a> ReverseSearcher<'a>,

Returns true if the given pattern matches a suffix of this string slice.

Returns false if it does not.

The pattern can be a &str, char, a slice of chars, or a function or closure that determines if a character matches.

Examples

let bananas = "bananas";

assert!(bananas.ends_with("anas"));
assert!(!bananas.ends_with("nana"));

pub fn find<P>(&self, pat: P) -> Option<usize>

where P: Pattern,

Returns the byte index of the first character of this string slice that matches the pattern.

Returns None if the pattern doesn’t match.

The pattern can be a &str, char, a slice of chars, or a function or closure that determines if a character matches.

Examples

Simple patterns:

let s = "Löwe 老虎 Léopard Gepardi";

assert_eq!(s.find('L'), Some(0));
assert_eq!(s.find('é'), Some(14));
assert_eq!(s.find("pard"), Some(17));

More complex patterns using point-free style and closures:

let s = "Löwe 老虎 Léopard";

assert_eq!(s.find(char::is_whitespace), Some(5));
assert_eq!(s.find(char::is_lowercase), Some(1));
assert_eq!(s.find(|c: char| c.is_whitespace() || c.is_lowercase()), Some(1));
assert_eq!(s.find(|c: char| (c < 'o') && (c > 'a')), Some(4));

Not finding the pattern:

let s = "Löwe 老虎 Léopard";
let x: &[_] = &['1', '2'];

assert_eq!(s.find(x), None);

pub fn rfind<P>(&self, pat: P) -> Option<usize>

where P: Pattern, <P as Pattern>::Searcher<'a>: for<'a> ReverseSearcher<'a>,

Returns the byte index for the first character of the last match of the pattern in this string slice.

Returns None if the pattern doesn’t match.

The pattern can be a &str, char, a slice of chars, or a function or closure that determines if a character matches.

Examples

Simple patterns:

let s = "Löwe 老虎 Léopard Gepardi";

assert_eq!(s.rfind('L'), Some(13));
assert_eq!(s.rfind('é'), Some(14));
assert_eq!(s.rfind("pard"), Some(24));

More complex patterns with closures:

let s = "Löwe 老虎 Léopard";

assert_eq!(s.rfind(char::is_whitespace), Some(12));
assert_eq!(s.rfind(char::is_lowercase), Some(20));

Not finding the pattern:

let s = "Löwe 老虎 Léopard";
let x: &[_] = &['1', '2'];

assert_eq!(s.rfind(x), None);

pub fn split<P>(&self, pat: P) -> Split<'_, P>

where P: Pattern,

Returns an iterator over substrings of this string slice, separated by characters matched by a pattern.

The pattern can be a &str, char, a slice of chars, or a function or closure that determines if a character matches.

If there are no matches the full string slice is returned as the only item in the iterator.

Iterator behavior

The returned iterator will be a DoubleEndedIterator if the pattern allows a reverse search and forward/reverse search yields the same elements. This is true for, e.g., char, but not for &str.

If the pattern allows a reverse search but its results might differ from a forward search, the rsplit method can be used.

Examples

Simple patterns:

let v: Vec<&str> = "Mary had a little lamb".split(' ').collect();
assert_eq!(v, ["Mary", "had", "a", "little", "lamb"]);

let v: Vec<&str> = "".split('X').collect();
assert_eq!(v, [""]);

let v: Vec<&str> = "lionXXtigerXleopard".split('X').collect();
assert_eq!(v, ["lion", "", "tiger", "leopard"]);

let v: Vec<&str> = "lion::tiger::leopard".split("::").collect();
assert_eq!(v, ["lion", "tiger", "leopard"]);

let v: Vec<&str> = "AABBCC".split("DD").collect();
assert_eq!(v, ["AABBCC"]);

let v: Vec<&str> = "abc1def2ghi".split(char::is_numeric).collect();
assert_eq!(v, ["abc", "def", "ghi"]);

let v: Vec<&str> = "lionXtigerXleopard".split(char::is_uppercase).collect();
assert_eq!(v, ["lion", "tiger", "leopard"]);

If the pattern is a slice of chars, split on each occurrence of any of the characters:

let v: Vec<&str> = "2020-11-03 23:59".split(&['-', ' ', ':', '@'][..]).collect();
assert_eq!(v, ["2020", "11", "03", "23", "59"]);

A more complex pattern, using a closure:

let v: Vec<&str> = "abc1defXghi".split(|c| c == '1' || c == 'X').collect();
assert_eq!(v, ["abc", "def", "ghi"]);

If a string contains multiple contiguous separators, you will end up with empty strings in the output:

let x = "||||a||b|c".to_string();
let d: Vec<_> = x.split('|').collect();

assert_eq!(d, &["", "", "", "", "a", "", "b", "c"]);

Contiguous separators are separated by the empty string.

let x = "(///)".to_string();
let d: Vec<_> = x.split('/').collect();

assert_eq!(d, &["(", "", "", ")"]);

Separators at the start or end of a string are neighbored by empty strings.

let d: Vec<_> = "010".split("0").collect();
assert_eq!(d, &["", "1", ""]);

When the empty string is used as a separator, it separates every character in the string, along with the beginning and end of the string.

let f: Vec<_> = "rust".split("").collect();
assert_eq!(f, &["", "r", "u", "s", "t", ""]);

Contiguous separators can lead to possibly surprising behavior when whitespace is used as the separator. This code is correct:

let x = "    a  b c".to_string();
let d: Vec<_> = x.split(' ').collect();

assert_eq!(d, &["", "", "", "", "a", "", "b", "c"]);

It does not give you:

assert_eq!(d, &["a", "b", "c"]);

Use split_whitespace for this behavior.

pub fn split_inclusive<P>(&self, pat: P) -> SplitInclusive<'_, P>

where P: Pattern,

Returns an iterator over substrings of this string slice, separated by characters matched by a pattern.

Differs from the iterator produced by split in that split_inclusive leaves the matched part as the terminator of the substring.

The pattern can be a &str, char, a slice of chars, or a function or closure that determines if a character matches.

Examples

let v: Vec<&str> = "Mary had a little lamb\nlittle lamb\nlittle lamb."
    .split_inclusive('\n').collect();
assert_eq!(v, ["Mary had a little lamb\n", "little lamb\n", "little lamb."]);

If the last element of the string is matched, that element will be considered the terminator of the preceding substring. That substring will be the last item returned by the iterator.

let v: Vec<&str> = "Mary had a little lamb\nlittle lamb\nlittle lamb.\n"
    .split_inclusive('\n').collect();
assert_eq!(v, ["Mary had a little lamb\n", "little lamb\n", "little lamb.\n"]);

pub fn rsplit<P>(&self, pat: P) -> RSplit<'_, P>

where P: Pattern, <P as Pattern>::Searcher<'a>: for<'a> ReverseSearcher<'a>,

Returns an iterator over substrings of the given string slice, separated by characters matched by a pattern and yielded in reverse order.

The pattern can be a &str, char, a slice of chars, or a function or closure that determines if a character matches.

Iterator behavior

The returned iterator requires that the pattern supports a reverse search, and it will be a DoubleEndedIterator if a forward/reverse search yields the same elements.

For iterating from the front, the split method can be used.

Examples

Simple patterns:

let v: Vec<&str> = "Mary had a little lamb".rsplit(' ').collect();
assert_eq!(v, ["lamb", "little", "a", "had", "Mary"]);

let v: Vec<&str> = "".rsplit('X').collect();
assert_eq!(v, [""]);

let v: Vec<&str> = "lionXXtigerXleopard".rsplit('X').collect();
assert_eq!(v, ["leopard", "tiger", "", "lion"]);

let v: Vec<&str> = "lion::tiger::leopard".rsplit("::").collect();
assert_eq!(v, ["leopard", "tiger", "lion"]);

A more complex pattern, using a closure:

let v: Vec<&str> = "abc1defXghi".rsplit(|c| c == '1' || c == 'X').collect();
assert_eq!(v, ["ghi", "def", "abc"]);

pub fn split_terminator<P>(&self, pat: P) -> SplitTerminator<'_, P>

where P: Pattern,

Returns an iterator over substrings of the given string slice, separated by characters matched by a pattern.

The pattern can be a &str, char, a slice of chars, or a function or closure that determines if a character matches.

Equivalent to split, except that the trailing substring is skipped if empty.

This method can be used for string data that is terminated, rather than separated by a pattern.

Iterator behavior

The returned iterator will be a DoubleEndedIterator if the pattern allows a reverse search and forward/reverse search yields the same elements. This is true for, e.g., char, but not for &str.

If the pattern allows a reverse search but its results might differ from a forward search, the rsplit_terminator method can be used.

Examples

let v: Vec<&str> = "A.B.".split_terminator('.').collect();
assert_eq!(v, ["A", "B"]);

let v: Vec<&str> = "A..B..".split_terminator(".").collect();
assert_eq!(v, ["A", "", "B", ""]);

let v: Vec<&str> = "A.B:C.D".split_terminator(&['.', ':'][..]).collect();
assert_eq!(v, ["A", "B", "C", "D"]);

pub fn rsplit_terminator<P>(&self, pat: P) -> RSplitTerminator<'_, P>

where P: Pattern, <P as Pattern>::Searcher<'a>: for<'a> ReverseSearcher<'a>,

Returns an iterator over substrings of self, separated by characters matched by a pattern and yielded in reverse order.

The pattern can be a &str, char, a slice of chars, or a function or closure that determines if a character matches.

Equivalent to split, except that the trailing substring is skipped if empty.

This method can be used for string data that is terminated, rather than separated by a pattern.

Iterator behavior

The returned iterator requires that the pattern supports a reverse search, and it will be double ended if a forward/reverse search yields the same elements.

For iterating from the front, the split_terminator method can be used.

Examples

let v: Vec<&str> = "A.B.".rsplit_terminator('.').collect();
assert_eq!(v, ["B", "A"]);

let v: Vec<&str> = "A..B..".rsplit_terminator(".").collect();
assert_eq!(v, ["", "B", "", "A"]);

let v: Vec<&str> = "A.B:C.D".rsplit_terminator(&['.', ':'][..]).collect();
assert_eq!(v, ["D", "C", "B", "A"]);

pub fn splitn<P>(&self, n: usize, pat: P) -> SplitN<'_, P>

where P: Pattern,

Returns an iterator over substrings of the given string slice, separated by a pattern, restricted to returning at most n items.

If n substrings are returned, the last substring (the nth substring) will contain the remainder of the string.

The pattern can be a &str, char, a slice of chars, or a function or closure that determines if a character matches.

Iterator behavior

The returned iterator will not be double ended, because it is not efficient to support.

If the pattern allows a reverse search, the rsplitn method can be used.

Examples

Simple patterns:

let v: Vec<&str> = "Mary had a little lambda".splitn(3, ' ').collect();
assert_eq!(v, ["Mary", "had", "a little lambda"]);

let v: Vec<&str> = "lionXXtigerXleopard".splitn(3, "X").collect();
assert_eq!(v, ["lion", "", "tigerXleopard"]);

let v: Vec<&str> = "abcXdef".splitn(1, 'X').collect();
assert_eq!(v, ["abcXdef"]);

let v: Vec<&str> = "".splitn(1, 'X').collect();
assert_eq!(v, [""]);

A more complex pattern, using a closure:

let v: Vec<&str> = "abc1defXghi".splitn(2, |c| c == '1' || c == 'X').collect();
assert_eq!(v, ["abc", "defXghi"]);

pub fn rsplitn<P>(&self, n: usize, pat: P) -> RSplitN<'_, P>

where P: Pattern, <P as Pattern>::Searcher<'a>: for<'a> ReverseSearcher<'a>,

Returns an iterator over substrings of this string slice, separated by a pattern, starting from the end of the string, restricted to returning at most n items.

If n substrings are returned, the last substring (the nth substring) will contain the remainder of the string.

The pattern can be a &str, char, a slice of chars, or a function or closure that determines if a character matches.

Iterator behavior

The returned iterator will not be double ended, because it is not efficient to support.

For splitting from the front, the splitn method can be used.

Examples

Simple patterns:

let v: Vec<&str> = "Mary had a little lamb".rsplitn(3, ' ').collect();
assert_eq!(v, ["lamb", "little", "Mary had a"]);

let v: Vec<&str> = "lionXXtigerXleopard".rsplitn(3, 'X').collect();
assert_eq!(v, ["leopard", "tiger", "lionX"]);

let v: Vec<&str> = "lion::tiger::leopard".rsplitn(2, "::").collect();
assert_eq!(v, ["leopard", "lion::tiger"]);

A more complex pattern, using a closure:

let v: Vec<&str> = "abc1defXghi".rsplitn(2, |c| c == '1' || c == 'X').collect();
assert_eq!(v, ["ghi", "abc1def"]);

pub fn split_once<P>(&self, delimiter: P) -> Option<(&str, &str)>

where P: Pattern,

Splits the string on the first occurrence of the specified delimiter and returns prefix before delimiter and suffix after delimiter.

Examples

assert_eq!("cfg".split_once('='), None);
assert_eq!("cfg=".split_once('='), Some(("cfg", "")));
assert_eq!("cfg=foo".split_once('='), Some(("cfg", "foo")));
assert_eq!("cfg=foo=bar".split_once('='), Some(("cfg", "foo=bar")));

pub fn rsplit_once<P>(&self, delimiter: P) -> Option<(&str, &str)>

where P: Pattern, <P as Pattern>::Searcher<'a>: for<'a> ReverseSearcher<'a>,

Splits the string on the last occurrence of the specified delimiter and returns prefix before delimiter and suffix after delimiter.

Examples

assert_eq!("cfg".rsplit_once('='), None);
assert_eq!("cfg=foo".rsplit_once('='), Some(("cfg", "foo")));
assert_eq!("cfg=foo=bar".rsplit_once('='), Some(("cfg=foo", "bar")));

pub fn matches<P>(&self, pat: P) -> Matches<'_, P>

where P: Pattern,

Returns an iterator over the disjoint matches of a pattern within the given string slice.

The pattern can be a &str, char, a slice of chars, or a function or closure that determines if a character matches.

Iterator behavior

The returned iterator will be a DoubleEndedIterator if the pattern allows a reverse search and forward/reverse search yields the same elements. This is true for, e.g., char, but not for &str.

If the pattern allows a reverse search but its results might differ from a forward search, the rmatches method can be used.

Examples

let v: Vec<&str> = "abcXXXabcYYYabc".matches("abc").collect();
assert_eq!(v, ["abc", "abc", "abc"]);

let v: Vec<&str> = "1abc2abc3".matches(char::is_numeric).collect();
assert_eq!(v, ["1", "2", "3"]);

pub fn rmatches<P>(&self, pat: P) -> RMatches<'_, P>

where P: Pattern, <P as Pattern>::Searcher<'a>: for<'a> ReverseSearcher<'a>,

Returns an iterator over the disjoint matches of a pattern within this string slice, yielded in reverse order.

The pattern can be a &str, char, a slice of chars, or a function or closure that determines if a character matches.

Iterator behavior

The returned iterator requires that the pattern supports a reverse search, and it will be a DoubleEndedIterator if a forward/reverse search yields the same elements.

For iterating from the front, the matches method can be used.

Examples

let v: Vec<&str> = "abcXXXabcYYYabc".rmatches("abc").collect();
assert_eq!(v, ["abc", "abc", "abc"]);

let v: Vec<&str> = "1abc2abc3".rmatches(char::is_numeric).collect();
assert_eq!(v, ["3", "2", "1"]);

pub fn match_indices<P>(&self, pat: P) -> MatchIndices<'_, P>

where P: Pattern,

Returns an iterator over the disjoint matches of a pattern within this string slice as well as the index that the match starts at.

For matches of pat within self that overlap, only the indices corresponding to the first match are returned.

The pattern can be a &str, char, a slice of chars, or a function or closure that determines if a character matches.

Iterator behavior

The returned iterator will be a DoubleEndedIterator if the pattern allows a reverse search and forward/reverse search yields the same elements. This is true for, e.g., char, but not for &str.

If the pattern allows a reverse search but its results might differ from a forward search, the rmatch_indices method can be used.

Examples

let v: Vec<_> = "abcXXXabcYYYabc".match_indices("abc").collect();
assert_eq!(v, [(0, "abc"), (6, "abc"), (12, "abc")]);

let v: Vec<_> = "1abcabc2".match_indices("abc").collect();
assert_eq!(v, [(1, "abc"), (4, "abc")]);

let v: Vec<_> = "ababa".match_indices("aba").collect();
assert_eq!(v, [(0, "aba")]); // only the first `aba`

pub fn rmatch_indices<P>(&self, pat: P) -> RMatchIndices<'_, P>

where P: Pattern, <P as Pattern>::Searcher<'a>: for<'a> ReverseSearcher<'a>,

Returns an iterator over the disjoint matches of a pattern within self, yielded in reverse order along with the index of the match.

For matches of pat within self that overlap, only the indices corresponding to the last match are returned.

The pattern can be a &str, char, a slice of chars, or a function or closure that determines if a character matches.

Iterator behavior

The returned iterator requires that the pattern supports a reverse search, and it will be a DoubleEndedIterator if a forward/reverse search yields the same elements.

For iterating from the front, the match_indices method can be used.

Examples

let v: Vec<_> = "abcXXXabcYYYabc".rmatch_indices("abc").collect();
assert_eq!(v, [(12, "abc"), (6, "abc"), (0, "abc")]);

let v: Vec<_> = "1abcabc2".rmatch_indices("abc").collect();
assert_eq!(v, [(4, "abc"), (1, "abc")]);

let v: Vec<_> = "ababa".rmatch_indices("aba").collect();
assert_eq!(v, [(2, "aba")]); // only the last `aba`

pub fn trim(&self) -> &str

Returns a string slice with leading and trailing whitespace removed.

‘Whitespace’ is defined according to the terms of the Unicode Derived Core Property White_Space, which includes newlines.

Examples

let s = "\n Hello\tworld\t\n";

assert_eq!("Hello\tworld", s.trim());

pub fn trim_start(&self) -> &str

Returns a string slice with leading whitespace removed.

‘Whitespace’ is defined according to the terms of the Unicode Derived Core Property White_Space, which includes newlines.

Text directionality

A string is a sequence of bytes. start in this context means the first position of that byte string; for a left-to-right language like English or Russian, this will be left side, and for right-to-left languages like Arabic or Hebrew, this will be the right side.

Examples

Basic usage:

let s = "\n Hello\tworld\t\n";
assert_eq!("Hello\tworld\t\n", s.trim_start());

Directionality:

let s = "  English  ";
assert!(Some('E') == s.trim_start().chars().next());

let s = "  עברית  ";
assert!(Some('ע') == s.trim_start().chars().next());

pub fn trim_end(&self) -> &str

Returns a string slice with trailing whitespace removed.

‘Whitespace’ is defined according to the terms of the Unicode Derived Core Property White_Space, which includes newlines.

Text directionality

A string is a sequence of bytes. end in this context means the last position of that byte string; for a left-to-right language like English or Russian, this will be right side, and for right-to-left languages like Arabic or Hebrew, this will be the left side.

Examples

Basic usage:

let s = "\n Hello\tworld\t\n";
assert_eq!("\n Hello\tworld", s.trim_end());

Directionality:

let s = "  English  ";
assert!(Some('h') == s.trim_end().chars().rev().next());

let s = "  עברית  ";
assert!(Some('ת') == s.trim_end().chars().rev().next());

pub fn trim_left(&self) -> &str

👎Deprecated since 1.33.0: superseded by trim_start

Returns a string slice with leading whitespace removed.

‘Whitespace’ is defined according to the terms of the Unicode Derived Core Property White_Space.

Text directionality

A string is a sequence of bytes. ‘Left’ in this context means the first position of that byte string; for a language like Arabic or Hebrew which are ‘right to left’ rather than ‘left to right’, this will be the right side, not the left.

Examples

Basic usage:

let s = " Hello\tworld\t";

assert_eq!("Hello\tworld\t", s.trim_left());

Directionality:

let s = "  English";
assert!(Some('E') == s.trim_left().chars().next());

let s = "  עברית";
assert!(Some('ע') == s.trim_left().chars().next());

pub fn trim_right(&self) -> &str

👎Deprecated since 1.33.0: superseded by trim_end

Returns a string slice with trailing whitespace removed.

‘Whitespace’ is defined according to the terms of the Unicode Derived Core Property White_Space.

Text directionality

A string is a sequence of bytes. ‘Right’ in this context means the last position of that byte string; for a language like Arabic or Hebrew which are ‘right to left’ rather than ‘left to right’, this will be the left side, not the right.

Examples

Basic usage:

let s = " Hello\tworld\t";

assert_eq!(" Hello\tworld", s.trim_right());

Directionality:

let s = "English  ";
assert!(Some('h') == s.trim_right().chars().rev().next());

let s = "עברית  ";
assert!(Some('ת') == s.trim_right().chars().rev().next());

pub fn trim_matches<P>(&self, pat: P) -> &str

where P: Pattern, <P as Pattern>::Searcher<'a>: for<'a> DoubleEndedSearcher<'a>,

Returns a string slice with all prefixes and suffixes that match a pattern repeatedly removed.

The pattern can be a char, a slice of chars, or a function or closure that determines if a character matches.

Examples

Simple patterns:

assert_eq!("11foo1bar11".trim_matches('1'), "foo1bar");
assert_eq!("123foo1bar123".trim_matches(char::is_numeric), "foo1bar");

let x: &[_] = &['1', '2'];
assert_eq!("12foo1bar12".trim_matches(x), "foo1bar");

A more complex pattern, using a closure:

assert_eq!("1foo1barXX".trim_matches(|c| c == '1' || c == 'X'), "foo1bar");

pub fn trim_start_matches<P>(&self, pat: P) -> &str

where P: Pattern,

Returns a string slice with all prefixes that match a pattern repeatedly removed.

The pattern can be a &str, char, a slice of chars, or a function or closure that determines if a character matches.

Text directionality

A string is a sequence of bytes. start in this context means the first position of that byte string; for a left-to-right language like English or Russian, this will be left side, and for right-to-left languages like Arabic or Hebrew, this will be the right side.

Examples

assert_eq!("11foo1bar11".trim_start_matches('1'), "foo1bar11");
assert_eq!("123foo1bar123".trim_start_matches(char::is_numeric), "foo1bar123");

let x: &[_] = &['1', '2'];
assert_eq!("12foo1bar12".trim_start_matches(x), "foo1bar12");

pub fn strip_prefix<P>(&self, prefix: P) -> Option<&str>

where P: Pattern,

Returns a string slice with the prefix removed.

If the string starts with the pattern prefix, returns the substring after the prefix, wrapped in Some. Unlike trim_start_matches, this method removes the prefix exactly once.

If the string does not start with prefix, returns None.

The pattern can be a &str, char, a slice of chars, or a function or closure that determines if a character matches.

Examples

assert_eq!("foo:bar".strip_prefix("foo:"), Some("bar"));
assert_eq!("foo:bar".strip_prefix("bar"), None);
assert_eq!("foofoo".strip_prefix("foo"), Some("foo"));

pub fn strip_suffix<P>(&self, suffix: P) -> Option<&str>

where P: Pattern, <P as Pattern>::Searcher<'a>: for<'a> ReverseSearcher<'a>,

Returns a string slice with the suffix removed.

If the string ends with the pattern suffix, returns the substring before the suffix, wrapped in Some. Unlike trim_end_matches, this method removes the suffix exactly once.

If the string does not end with suffix, returns None.

The pattern can be a &str, char, a slice of chars, or a function or closure that determines if a character matches.

Examples

assert_eq!("bar:foo".strip_suffix(":foo"), Some("bar"));
assert_eq!("bar:foo".strip_suffix("bar"), None);
assert_eq!("foofoo".strip_suffix("foo"), Some("foo"));

pub fn trim_prefix<P>(&self, prefix: P) -> &str

where P: Pattern,

🔬This is a nightly-only experimental API. (trim_prefix_suffix)

Returns a string slice with the optional prefix removed.

If the string starts with the pattern prefix, returns the substring after the prefix. Unlike strip_prefix, this method always returns &str for easy method chaining, instead of returning Option<&str>.

If the string does not start with prefix, returns the original string unchanged.

The pattern can be a &str, char, a slice of chars, or a function or closure that determines if a character matches.

Examples

#![feature(trim_prefix_suffix)]

// Prefix present - removes it
assert_eq!("foo:bar".trim_prefix("foo:"), "bar");
assert_eq!("foofoo".trim_prefix("foo"), "foo");

// Prefix absent - returns original string
assert_eq!("foo:bar".trim_prefix("bar"), "foo:bar");

// Method chaining example
assert_eq!("<https://example.com/>".trim_prefix('<').trim_suffix('>'), "https://example.com/");

pub fn trim_suffix<P>(&self, suffix: P) -> &str

where P: Pattern, <P as Pattern>::Searcher<'a>: for<'a> ReverseSearcher<'a>,

🔬This is a nightly-only experimental API. (trim_prefix_suffix)

Returns a string slice with the optional suffix removed.

If the string ends with the pattern suffix, returns the substring before the suffix. Unlike strip_suffix, this method always returns &str for easy method chaining, instead of returning Option<&str>.

If the string does not end with suffix, returns the original string unchanged.

The pattern can be a &str, char, a slice of chars, or a function or closure that determines if a character matches.

Examples

#![feature(trim_prefix_suffix)]

// Suffix present - removes it
assert_eq!("bar:foo".trim_suffix(":foo"), "bar");
assert_eq!("foofoo".trim_suffix("foo"), "foo");

// Suffix absent - returns original string
assert_eq!("bar:foo".trim_suffix("bar"), "bar:foo");

// Method chaining example
assert_eq!("<https://example.com/>".trim_prefix('<').trim_suffix('>'), "https://example.com/");

pub fn trim_end_matches<P>(&self, pat: P) -> &str

where P: Pattern, <P as Pattern>::Searcher<'a>: for<'a> ReverseSearcher<'a>,

Returns a string slice with all suffixes that match a pattern repeatedly removed.

The pattern can be a &str, char, a slice of chars, or a function or closure that determines if a character matches.

Text directionality

A string is a sequence of bytes. end in this context means the last position of that byte string; for a left-to-right language like English or Russian, this will be right side, and for right-to-left languages like Arabic or Hebrew, this will be the left side.

Examples

Simple patterns:

assert_eq!("11foo1bar11".trim_end_matches('1'), "11foo1bar");
assert_eq!("123foo1bar123".trim_end_matches(char::is_numeric), "123foo1bar");

let x: &[_] = &['1', '2'];
assert_eq!("12foo1bar12".trim_end_matches(x), "12foo1bar");

A more complex pattern, using a closure:

assert_eq!("1fooX".trim_end_matches(|c| c == '1' || c == 'X'), "1foo");

pub fn trim_left_matches<P>(&self, pat: P) -> &str

where P: Pattern,

👎Deprecated since 1.33.0: superseded by trim_start_matches

Returns a string slice with all prefixes that match a pattern repeatedly removed.

The pattern can be a &str, char, a slice of chars, or a function or closure that determines if a character matches.

Text directionality

A string is a sequence of bytes. ‘Left’ in this context means the first position of that byte string; for a language like Arabic or Hebrew which are ‘right to left’ rather than ‘left to right’, this will be the right side, not the left.

Examples

assert_eq!("11foo1bar11".trim_left_matches('1'), "foo1bar11");
assert_eq!("123foo1bar123".trim_left_matches(char::is_numeric), "foo1bar123");

let x: &[_] = &['1', '2'];
assert_eq!("12foo1bar12".trim_left_matches(x), "foo1bar12");

pub fn trim_right_matches<P>(&self, pat: P) -> &str

where P: Pattern, <P as Pattern>::Searcher<'a>: for<'a> ReverseSearcher<'a>,

👎Deprecated since 1.33.0: superseded by trim_end_matches

Returns a string slice with all suffixes that match a pattern repeatedly removed.

The pattern can be a &str, char, a slice of chars, or a function or closure that determines if a character matches.

Text directionality

A string is a sequence of bytes. ‘Right’ in this context means the last position of that byte string; for a language like Arabic or Hebrew which are ‘right to left’ rather than ‘left to right’, this will be the left side, not the right.

Examples

Simple patterns:

assert_eq!("11foo1bar11".trim_right_matches('1'), "11foo1bar");
assert_eq!("123foo1bar123".trim_right_matches(char::is_numeric), "123foo1bar");

let x: &[_] = &['1', '2'];
assert_eq!("12foo1bar12".trim_right_matches(x), "12foo1bar");

A more complex pattern, using a closure:

assert_eq!("1fooX".trim_right_matches(|c| c == '1' || c == 'X'), "1foo");

pub fn parse<F>(&self) -> Result<F, <F as FromStr>::Err>

where F: FromStr,

Parses this string slice into another type.

Because parse is so general, it can cause problems with type inference. As such, parse is one of the few times you’ll see the syntax affectionately known as the ‘turbofish’: ::<>. This helps the inference algorithm understand specifically which type you’re trying to parse into.

parse can parse into any type that implements the FromStr trait.

Errors

Will return Err if it’s not possible to parse this string slice into the desired type.

Examples

Basic usage:

let four: u32 = "4".parse().unwrap();

assert_eq!(4, four);

Using the ‘turbofish’ instead of annotating four:

let four = "4".parse::<u32>();

assert_eq!(Ok(4), four);

Failing to parse:

let nope = "j".parse::<u32>();

assert!(nope.is_err());

pub fn is_ascii(&self) -> bool

Checks if all characters in this string are within the ASCII range.

Examples

let ascii = "hello!\n";
let non_ascii = "Grüße, Jürgen ❤";

assert!(ascii.is_ascii());
assert!(!non_ascii.is_ascii());

pub fn as_ascii(&self) -> Option<&[AsciiChar]>

🔬This is a nightly-only experimental API. (ascii_char)

If this string slice is_ascii, returns it as a slice of ASCII characters, otherwise returns None.

pub unsafe fn as_ascii_unchecked(&self) -> &[AsciiChar]

🔬This is a nightly-only experimental API. (ascii_char)

Converts this string slice into a slice of ASCII characters, without checking whether they are valid.

Safety

Every character in this string must be ASCII, or else this is UB.

pub fn eq_ignore_ascii_case(&self, other: &str) -> bool

Checks that two strings are an ASCII case-insensitive match.

Same as to_ascii_lowercase(a) == to_ascii_lowercase(b), but without allocating and copying temporaries.

Examples

assert!("Ferris".eq_ignore_ascii_case("FERRIS"));
assert!("Ferrös".eq_ignore_ascii_case("FERRöS"));
assert!(!"Ferrös".eq_ignore_ascii_case("FERRÖS"));

pub fn trim_ascii_start(&self) -> &str

Returns a string slice with leading ASCII whitespace removed.

‘Whitespace’ refers to the definition used by u8::is_ascii_whitespace.

Examples

assert_eq!(" \t \u{3000}hello world\n".trim_ascii_start(), "\u{3000}hello world\n");
assert_eq!("  ".trim_ascii_start(), "");
assert_eq!("".trim_ascii_start(), "");

pub fn trim_ascii_end(&self) -> &str

Returns a string slice with trailing ASCII whitespace removed.

‘Whitespace’ refers to the definition used by u8::is_ascii_whitespace.

Examples

assert_eq!("\r hello world\u{3000}\n ".trim_ascii_end(), "\r hello world\u{3000}");
assert_eq!("  ".trim_ascii_end(), "");
assert_eq!("".trim_ascii_end(), "");

pub fn trim_ascii(&self) -> &str

Returns a string slice with leading and trailing ASCII whitespace removed.

‘Whitespace’ refers to the definition used by u8::is_ascii_whitespace.

Examples

assert_eq!("\r hello world\n ".trim_ascii(), "hello world");
assert_eq!("  ".trim_ascii(), "");
assert_eq!("".trim_ascii(), "");

pub fn escape_debug(&self) -> EscapeDebug<'_>

Returns an iterator that escapes each char in self with char::escape_debug.

Note: only extended grapheme codepoints that begin the string will be escaped.

Examples

As an iterator:

for c in "❤\n!".escape_debug() {
    print!("{c}");
}
println!();

Using println! directly:

println!("{}", "❤\n!".escape_debug());

Both are equivalent to:

println!("❤\\n!");

Using to_string:

assert_eq!("❤\n!".escape_debug().to_string(), "❤\\n!");

pub fn escape_default(&self) -> EscapeDefault<'_>

Returns an iterator that escapes each char in self with char::escape_default.

Examples

As an iterator:

for c in "❤\n!".escape_default() {
    print!("{c}");
}
println!();

Using println! directly:

println!("{}", "❤\n!".escape_default());

Both are equivalent to:

println!("\\u{{2764}}\\n!");

Using to_string:

assert_eq!("❤\n!".escape_default().to_string(), "\\u{2764}\\n!");

pub fn escape_unicode(&self) -> EscapeUnicode<'_>

Returns an iterator that escapes each char in self with char::escape_unicode.

Examples

As an iterator:

for c in "❤\n!".escape_unicode() {
    print!("{c}");
}
println!();

Using println! directly:

println!("{}", "❤\n!".escape_unicode());

Both are equivalent to:

println!("\\u{{2764}}\\u{{a}}\\u{{21}}");

Using to_string:

assert_eq!("❤\n!".escape_unicode().to_string(), "\\u{2764}\\u{a}\\u{21}");

pub fn substr_range(&self, substr: &str) -> Option<Range<usize>>

🔬This is a nightly-only experimental API. (substr_range)

Returns the range that a substring points to.

Returns None if substr does not point within self.

Unlike str::find, this does not search through the string. Instead, it uses pointer arithmetic to find where in the string substr is derived from.

This is useful for extending str::split and similar methods.

Note that this method may return false positives (typically either Some(0..0) or Some(self.len()..self.len())) if substr is a zero-length str that points at the beginning or end of another, independent, str.

Examples

#![feature(substr_range)]

let data = "a, b, b, a";
let mut iter = data.split(", ").map(|s| data.substr_range(s).unwrap());

assert_eq!(iter.next(), Some(0..1));
assert_eq!(iter.next(), Some(3..4));
assert_eq!(iter.next(), Some(6..7));
assert_eq!(iter.next(), Some(9..10));

pub fn as_str(&self) -> &str

🔬This is a nightly-only experimental API. (str_as_str)

Returns the same string as a string slice &str.

This method is redundant when used directly on &str, but it helps dereferencing other string-like types to string slices, for example references to Box<str> or Arc<str>.

pub fn replace<P>(&self, from: P, to: &str) -> String

where P: Pattern,

Replaces all matches of a pattern with another string.

replace creates a new String, and copies the data from this string slice into it. While doing so, it attempts to find matches of a pattern. If it finds any, it replaces them with the replacement string slice.

Examples

let s = "this is old";

assert_eq!("this is new", s.replace("old", "new"));
assert_eq!("than an old", s.replace("is", "an"));

When the pattern doesn’t match, it returns this string slice as String:

let s = "this is old";
assert_eq!(s, s.replace("cookie monster", "little lamb"));

pub fn replacen<P>(&self, pat: P, to: &str, count: usize) -> String

where P: Pattern,

Replaces first N matches of a pattern with another string.

replacen creates a new String, and copies the data from this string slice into it. While doing so, it attempts to find matches of a pattern. If it finds any, it replaces them with the replacement string slice at most count times.

Examples

let s = "foo foo 123 foo";
assert_eq!("new new 123 foo", s.replacen("foo", "new", 2));
assert_eq!("faa fao 123 foo", s.replacen('o', "a", 3));
assert_eq!("foo foo new23 foo", s.replacen(char::is_numeric, "new", 1));

When the pattern doesn’t match, it returns this string slice as String:

let s = "this is old";
assert_eq!(s, s.replacen("cookie monster", "little lamb", 10));

pub fn to_lowercase(&self) -> String

Returns the lowercase equivalent of this string slice, as a new String.

‘Lowercase’ is defined according to the terms of the Unicode Derived Core Property Lowercase.

Since some characters can expand into multiple characters when changing the case, this function returns a String instead of modifying the parameter in-place.

Examples

Basic usage:

let s = "HELLO";

assert_eq!("hello", s.to_lowercase());

A tricky example, with sigma:

let sigma = "Σ";

assert_eq!("σ", sigma.to_lowercase());

// but at the end of a word, it's ς, not σ:
let odysseus = "ὈΔΥΣΣΕΎΣ";

assert_eq!("ὀδυσσεύς", odysseus.to_lowercase());

Languages without case are not changed:

let new_year = "农历新年";

assert_eq!(new_year, new_year.to_lowercase());

pub fn to_uppercase(&self) -> String

Returns the uppercase equivalent of this string slice, as a new String.

‘Uppercase’ is defined according to the terms of the Unicode Derived Core Property Uppercase.

Since some characters can expand into multiple characters when changing the case, this function returns a String instead of modifying the parameter in-place.

Examples

Basic usage:

let s = "hello";

assert_eq!("HELLO", s.to_uppercase());

Scripts without case are not changed:

let new_year = "农历新年";

assert_eq!(new_year, new_year.to_uppercase());

One character can become multiple:

let s = "tschüß";

assert_eq!("TSCHÜSS", s.to_uppercase());

pub fn repeat(&self, n: usize) -> String

Creates a new String by repeating a string n times.

Panics

This function will panic if the capacity would overflow.

Examples

Basic usage:

assert_eq!("abc".repeat(4), String::from("abcabcabcabc"));

A panic upon overflow:

// this will panic at runtime
let huge = "0123456789abcdef".repeat(usize::MAX);

pub fn to_ascii_uppercase(&self) -> String

Returns a copy of this string where each character is mapped to its ASCII upper case equivalent.

ASCII letters ‘a’ to ‘z’ are mapped to ‘A’ to ‘Z’, but non-ASCII letters are unchanged.

To uppercase the value in-place, use make_ascii_uppercase.

To uppercase ASCII characters in addition to non-ASCII characters, use to_uppercase.

Examples

let s = "Grüße, Jürgen ❤";

assert_eq!("GRüßE, JüRGEN ❤", s.to_ascii_uppercase());

pub fn to_ascii_lowercase(&self) -> String

Returns a copy of this string where each character is mapped to its ASCII lower case equivalent.

ASCII letters ‘A’ to ‘Z’ are mapped to ‘a’ to ‘z’, but non-ASCII letters are unchanged.

To lowercase the value in-place, use make_ascii_lowercase.

To lowercase ASCII characters in addition to non-ASCII characters, use to_lowercase.

Examples

let s = "Grüße, Jürgen ❤";

assert_eq!("grüße, jürgen ❤", s.to_ascii_lowercase());

Trait Implementations

impl AnyUriRef for UriBuf

fn components(&self) -> UriRawComponents<'_>

Returns a UriRawComponents instance which contains all of the components for this URI reference.

fn write_to<W: Write + ?Sized>(&self, write: &mut W) -> Result<(), Error>

Serializes this URI to anything implementing core::fmt::Write. Override with care!

fn is_empty(&self) -> bool

Returns true if the underlying URI-reference is actually the empty reference.

fn uri_type(&self) -> UriType

Gets the UriType of the underlying URI-reference.

fn to_uri_ref_buf(&self) -> UriRefBuf

Creates a new UriRefBuf from this AnyUriRef.

fn write_resolved<W: Write + ?Sized, D: AnyUriRef + ?Sized>( &self, dest: &D, output: &mut W, ) -> Result<(), ResolveError>

Writes out to a core::fmt::Write instance the result of performing URI resolution against target, with self being the base URI.

fn resolved<W: AnyUriRef + ?Sized>( &self, dest: &W, ) -> Result<UriRefBuf, ResolveError>

Creates a new UriRefBuf that contains the result of performing URI resolution with dest.

fn display(&self) -> UriDisplay<'_, Self>

Wraps this AnyUriRef instance in a UriDisplay object for use with formatting macros like write! and format!.

impl AsRef<String> for UriBuf

fn as_ref(&self) -> &String

Converts this type into a shared reference of the (usually inferred) input type.

impl AsRef<Uri> for UriBuf

fn as_ref(&self) -> &Uri

Converts this type into a shared reference of the (usually inferred) input type.

impl AsRef<UriBuf> for UriBuf

fn as_ref(&self) -> &UriBuf

Converts this type into a shared reference of the (usually inferred) input type.

impl AsRef<UriRefBuf> for UriBuf

fn as_ref(&self) -> &UriRefBuf

Converts this type into a shared reference of the (usually inferred) input type.

impl AsRef<str> for UriBuf

fn as_ref(&self) -> &str

Converts this type into a shared reference of the (usually inferred) input type.

impl Borrow<Uri> for UriBuf

fn borrow(&self) -> &Uri

Immutably borrows from an owned value.

impl Clone for UriBuf

fn clone(&self) -> UriBuf

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for UriBuf

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl Display for UriBuf

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl From<&Uri> for UriBuf

fn from(x: &Uri) -> Self

Converts to this type from the input type.

impl From<&UriBuf> for UriBuf

fn from(x: &UriBuf) -> Self

Converts to this type from the input type.

impl From<UriBuf> for String

fn from(x: UriBuf) -> Self

Converts to this type from the input type.

impl From<UriBuf> for UriRefBuf

fn from(x: UriBuf) -> Self

Converts to this type from the input type.

impl Hash for UriBuf

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for UriBuf

fn cmp(&self, other: &Self) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl<T: AsRef<str> + ?Sized> PartialEq<T> for UriBuf

fn eq(&self, other: &T) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<T: AsRef<str> + ?Sized> PartialOrd<T> for UriBuf

fn partial_cmp(&self, other: &T) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl Deref for UriBuf

type Target = Uri

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl Eq for UriBuf