Struct csv::ByteRecord
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pub struct ByteRecord(_);
A single CSV record stored as raw bytes.
A byte record permits reading or writing CSV rows that are not UTF-8.
In general, you should prefer using a
StringRecord
since it is more ergonomic, but a ByteRecord
is provided in case you need
it.
If you are using the Serde (de)serialization APIs, then you probably never
need to interact with a ByteRecord
or a StringRecord
.
Two ByteRecord
s are compared on the basis of their field data. Any
position information associated with the records is ignored.
Methods
impl ByteRecord
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pub fn new() -> ByteRecord
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Create a new empty ByteRecord
.
Note that you may find the ByteRecord::from
constructor more
convenient, which is provided by an impl on the From
trait.
Example: create an empty record
use csv::ByteRecord; let record = ByteRecord::new(); assert_eq!(record.len(), 0);
Example: initialize a record from a Vec
use csv::ByteRecord; let record = ByteRecord::from(vec!["a", "b", "c"]); assert_eq!(record.len(), 3);
pub fn with_capacity(buffer: usize, fields: usize) -> ByteRecord
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Create a new empty ByteRecord
with the given capacity settings.
buffer
refers to the capacity of the buffer used to store the
actual row contents. fields
refers to the number of fields one
might expect to store.
pub fn deserialize<'de, D: Deserialize<'de>>(
&'de self,
headers: Option<&'de ByteRecord>
) -> Result<D>
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&'de self,
headers: Option<&'de ByteRecord>
) -> Result<D>
Deserialize this record.
The D
type parameter refers to the type that this record should be
deserialized into. The 'de
lifetime refers to the lifetime of the
ByteRecord
. The 'de
lifetime permits deserializing into structs
that borrow field data from this record.
An optional headers
parameter permits deserializing into a struct
based on its field names (corresponding to header values) rather than
the order in which the fields are defined.
Example: without headers
This shows how to deserialize a single row into a struct based on the
order in which fields occur. This example also shows how to borrow
fields from the ByteRecord
, which results in zero allocation
deserialization.
extern crate csv; #[macro_use] extern crate serde_derive; use std::error::Error; use csv::ByteRecord; #[derive(Deserialize)] struct Row<'a> { city: &'a str, country: &'a str, population: u64, } fn example() -> Result<(), Box<Error>> { let record = ByteRecord::from(vec![ "Boston", "United States", "4628910", ]); let row: Row = record.deserialize(None)?; assert_eq!(row.city, "Boston"); assert_eq!(row.country, "United States"); assert_eq!(row.population, 4628910); Ok(()) }
Example: with headers
This example is like the previous one, but shows how to deserialize into a struct based on the struct's field names. For this to work, you must provide a header row.
This example also shows that you can deserialize into owned data
types (e.g., String
) instead of borrowed data types (e.g., &str
).
extern crate csv; #[macro_use] extern crate serde_derive; use std::error::Error; use csv::ByteRecord; #[derive(Deserialize)] struct Row { city: String, country: String, population: u64, } fn example() -> Result<(), Box<Error>> { // Notice that the fields are not in the same order // as the fields in the struct! let header = ByteRecord::from(vec![ "country", "city", "population", ]); let record = ByteRecord::from(vec![ "United States", "Boston", "4628910", ]); let row: Row = record.deserialize(Some(&header))?; assert_eq!(row.city, "Boston"); assert_eq!(row.country, "United States"); assert_eq!(row.population, 4628910); Ok(()) }
ⓘImportant traits for ByteRecordIter<'r>pub fn iter(&self) -> ByteRecordIter
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Returns an iterator over all fields in this record.
Example
This example shows how to iterate over each field in a ByteRecord
.
use csv::ByteRecord; let record = ByteRecord::from(vec!["a", "b", "c"]); for field in record.iter() { assert!(field == b"a" || field == b"b" || field == b"c"); }
pub fn get(&self, i: usize) -> Option<&[u8]>
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Return the field at index i
.
If no field at index i
exists, then this returns None
.
Example
use csv::ByteRecord; let record = ByteRecord::from(vec!["a", "b", "c"]); assert_eq!(record.get(1), Some(&b"b"[..])); assert_eq!(record.get(3), None);
pub fn is_empty(&self) -> bool
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Returns true if and only if this record is empty.
Example
use csv::ByteRecord; assert!(ByteRecord::new().is_empty());
pub fn len(&self) -> usize
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Returns the number of fields in this record.
Example
use csv::ByteRecord; let record = ByteRecord::from(vec!["a", "b", "c"]); assert_eq!(record.len(), 3);
pub fn truncate(&mut self, n: usize)
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Truncate this record to n
fields.
If n
is greater than the number of fields in this record, then this
has no effect.
Example
use csv::ByteRecord; let mut record = ByteRecord::from(vec!["a", "b", "c"]); assert_eq!(record.len(), 3); record.truncate(1); assert_eq!(record.len(), 1); assert_eq!(record, vec!["a"]);
pub fn clear(&mut self)
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Clear this record so that it has zero fields.
This is equivalent to calling truncate(0)
.
Note that it is not necessary to clear the record to reuse it with the CSV reader.
Example
use csv::ByteRecord; let mut record = ByteRecord::from(vec!["a", "b", "c"]); assert_eq!(record.len(), 3); record.clear(); assert_eq!(record.len(), 0);
pub fn trim(&mut self)
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Trim the fields of this record so that leading and trailing whitespace is removed.
This method uses the ASCII definition of whitespace. That is, only
bytes in the class [\t\n\v\f\r ]
are trimmed.
Example
use csv::ByteRecord; let mut record = ByteRecord::from(vec![ " ", "\tfoo", "bar ", "b a z", ]); record.trim(); assert_eq!(record, vec!["", "foo", "bar", "b a z"]);
pub fn push_field(&mut self, field: &[u8])
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Add a new field to this record.
Example
use csv::ByteRecord; let mut record = ByteRecord::new(); record.push_field(b"foo"); assert_eq!(&record[0], b"foo");
pub fn position(&self) -> Option<&Position>
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Return the position of this record, if available.
Example
extern crate csv; use std::error::Error; use csv::{ByteRecord, ReaderBuilder}; fn example() -> Result<(), Box<Error>> { let mut record = ByteRecord::new(); let mut rdr = ReaderBuilder::new() .has_headers(false) .from_reader("a,b,c\nx,y,z".as_bytes()); assert!(rdr.read_byte_record(&mut record)?); { let pos = record.position().expect("a record position"); assert_eq!(pos.byte(), 0); assert_eq!(pos.line(), 1); assert_eq!(pos.record(), 0); } assert!(rdr.read_byte_record(&mut record)?); { let pos = record.position().expect("a record position"); assert_eq!(pos.byte(), 6); assert_eq!(pos.line(), 2); assert_eq!(pos.record(), 1); } // Finish the CSV reader for good measure. assert!(!rdr.read_byte_record(&mut record)?); Ok(()) }
pub fn set_position(&mut self, pos: Option<Position>)
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Set the position of this record.
Example
use csv::{ByteRecord, Position}; let mut record = ByteRecord::from(vec!["a", "b", "c"]); let mut pos = Position::new(); pos.set_byte(100); pos.set_line(4); pos.set_record(2); record.set_position(Some(pos.clone())); assert_eq!(record.position(), Some(&pos));
pub fn range(&self, i: usize) -> Option<Range<usize>>
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Return the start and end position of a field in this record.
If no such field exists at the given index, then return None
.
The range returned can be used with the slice returned by as_slice
.
Example
use csv::ByteRecord; let record = ByteRecord::from(vec!["foo", "quux", "z"]); let range = record.range(1).expect("a record range"); assert_eq!(&record.as_slice()[range], &b"quux"[..]);
pub fn as_slice(&self) -> &[u8]
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Return the entire row as a single byte slice. The slice returned stores
all fields contiguously. The boundaries of each field can be determined
via the range
method.
Example
use csv::ByteRecord; let record = ByteRecord::from(vec!["foo", "quux", "z"]); assert_eq!(record.as_slice(), &b"fooquuxz"[..]);
Trait Implementations
impl Clone for ByteRecord
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fn clone(&self) -> ByteRecord
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Returns a copy of the value. Read more
fn clone_from(&mut self, source: &Self)
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Performs copy-assignment from source
. Read more
impl Eq for ByteRecord
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impl PartialEq for ByteRecord
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fn eq(&self, other: &ByteRecord) -> bool
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This method tests for self
and other
values to be equal, and is used by ==
. Read more
fn ne(&self, other: &Rhs) -> bool
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This method tests for !=
.
impl<T: AsRef<[u8]>> PartialEq<Vec<T>> for ByteRecord
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fn eq(&self, other: &Vec<T>) -> bool
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This method tests for self
and other
values to be equal, and is used by ==
. Read more
fn ne(&self, other: &Rhs) -> bool
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This method tests for !=
.
impl<'a, T: AsRef<[u8]>> PartialEq<Vec<T>> for &'a ByteRecord
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fn eq(&self, other: &Vec<T>) -> bool
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This method tests for self
and other
values to be equal, and is used by ==
. Read more
fn ne(&self, other: &Rhs) -> bool
1.0.0[src]
This method tests for !=
.
impl<T: AsRef<[u8]>> PartialEq<[T]> for ByteRecord
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fn eq(&self, other: &[T]) -> bool
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This method tests for self
and other
values to be equal, and is used by ==
. Read more
fn ne(&self, other: &Rhs) -> bool
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This method tests for !=
.
impl<'a, T: AsRef<[u8]>> PartialEq<[T]> for &'a ByteRecord
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fn eq(&self, other: &[T]) -> bool
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This method tests for self
and other
values to be equal, and is used by ==
. Read more
fn ne(&self, other: &Rhs) -> bool
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This method tests for !=
.
impl Debug for ByteRecord
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fn fmt(&self, f: &mut Formatter) -> Result
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Formats the value using the given formatter. Read more
impl Default for ByteRecord
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fn default() -> ByteRecord
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Returns the "default value" for a type. Read more
impl Index<usize> for ByteRecord
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type Output = [u8]
The returned type after indexing.
fn index(&self, i: usize) -> &[u8]
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Performs the indexing (container[index]
) operation.
impl From<StringRecord> for ByteRecord
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fn from(record: StringRecord) -> ByteRecord
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Performs the conversion.
impl<T: AsRef<[u8]>> From<Vec<T>> for ByteRecord
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fn from(xs: Vec<T>) -> ByteRecord
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Performs the conversion.
impl<'a, T: AsRef<[u8]>> From<&'a [T]> for ByteRecord
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fn from(xs: &'a [T]) -> ByteRecord
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Performs the conversion.
impl<T: AsRef<[u8]>> FromIterator<T> for ByteRecord
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fn from_iter<I: IntoIterator<Item = T>>(iter: I) -> ByteRecord
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Creates a value from an iterator. Read more
impl<T: AsRef<[u8]>> Extend<T> for ByteRecord
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fn extend<I: IntoIterator<Item = T>>(&mut self, iter: I)
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Extends a collection with the contents of an iterator. Read more
impl<'r> IntoIterator for &'r ByteRecord
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type IntoIter = ByteRecordIter<'r>
Which kind of iterator are we turning this into?
type Item = &'r [u8]
The type of the elements being iterated over.
ⓘImportant traits for ByteRecordIter<'r>fn into_iter(self) -> ByteRecordIter<'r>
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Creates an iterator from a value. Read more