[][src]Struct csv::ByteRecord

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. However, there are some circumstances in which you might need to use a raw record type while still using Serde. For example, if you need to deserialize possibly invalid UTF-8 fields, then you'll need to first read your record into a ByteRecord, and then use ByteRecord::deserialize to run Serde. Another reason for using the raw record deserialization APIs is if you're using Serde to read into borrowed data such as a &'a str or a &'a [u8].

Two ByteRecords 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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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);

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.

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>

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");
}

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);

Returns true if and only if this record is empty.

Example

use csv::ByteRecord;

assert!(ByteRecord::new().is_empty());

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);

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"]);

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);

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"]);

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");

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(())
}

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));

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"[..]);

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 PartialEq<ByteRecord> for ByteRecord
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This method tests for !=.

impl<T: AsRef<[u8]>> PartialEq<Vec<T>> for ByteRecord
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This method tests for !=.

impl<'a, T: AsRef<[u8]>> PartialEq<Vec<T>> for &'a ByteRecord
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This method tests for !=.

impl<T: AsRef<[u8]>> PartialEq<[T]> for ByteRecord
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This method tests for !=.

impl<'a, T: AsRef<[u8]>> PartialEq<[T]> for &'a ByteRecord
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This method tests for !=.

impl From<StringRecord> for ByteRecord
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impl<T: AsRef<[u8]>> From<Vec<T>> for ByteRecord
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impl<'a, T: AsRef<[u8]>> From<&'a [T]> for ByteRecord
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impl Clone for ByteRecord
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Performs copy-assignment from source. Read more

impl<'r> IntoIterator for &'r ByteRecord
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Which kind of iterator are we turning this into?

The type of the elements being iterated over.

impl Eq for ByteRecord
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impl<T: AsRef<[u8]>> Extend<T> for ByteRecord
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impl Default for ByteRecord
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impl Debug for ByteRecord
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impl Index<usize> for ByteRecord
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The returned type after indexing.

impl<T: AsRef<[u8]>> FromIterator<T> for ByteRecord
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Auto Trait Implementations

impl Send for ByteRecord

impl Sync for ByteRecord

Blanket Implementations

impl<T> From for T
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impl<T, U> Into for T where
    U: From<T>, 
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impl<T> ToOwned for T where
    T: Clone
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impl<T, U> TryFrom for T where
    T: From<U>, 
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🔬 This is a nightly-only experimental API. (try_from)

The type returned in the event of a conversion error.

impl<T> Borrow for T where
    T: ?Sized
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impl<T> BorrowMut for T where
    T: ?Sized
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impl<T, U> TryInto for T where
    U: TryFrom<T>, 
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🔬 This is a nightly-only experimental API. (try_from)

The type returned in the event of a conversion error.

impl<T> Any for T where
    T: 'static + ?Sized
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