Crate csv

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Expand description

The csv crate provides a fast and flexible CSV reader and writer, with support for Serde.

The tutorial is a good place to start if you’re new to Rust.

The cookbook will give you a variety of complete Rust programs that do CSV reading and writing.

Brief overview

If you’re new to Rust, you might find the tutorial to be a good place to start.

The primary types in this crate are Reader and Writer, for reading and writing CSV data respectively. Correspondingly, to support CSV data with custom field or record delimiters (among many other things), you should use either a ReaderBuilder or a WriterBuilder, depending on whether you’re reading or writing CSV data.

Unless you’re using Serde, the standard CSV record types are StringRecord and ByteRecord. StringRecord should be used when you know your data to be valid UTF-8. For data that may be invalid UTF-8, ByteRecord is suitable.

Finally, the set of errors is described by the Error type.

The rest of the types in this crate mostly correspond to more detailed errors, position information, configuration knobs or iterator types.

Setup

Run cargo add csv to add the latest version of the csv crate to your Cargo.toml.

If you want to use Serde’s custom derive functionality on your custom structs, then run cargo add serde --features derive to add the serde crate with its derive feature enabled to your Cargo.toml.

Example

This example shows how to read CSV data from stdin and print each record to stdout.

There are more examples in the cookbook.

use std::{error::Error, io, process};

fn example() -> Result<(), Box<dyn Error>> {
    // Build the CSV reader and iterate over each record.
    let mut rdr = csv::Reader::from_reader(io::stdin());
    for result in rdr.records() {
        // The iterator yields Result<StringRecord, Error>, so we check the
        // error here.
        let record = result?;
        println!("{:?}", record);
    }
    Ok(())
}

fn main() {
    if let Err(err) = example() {
        println!("error running example: {}", err);
        process::exit(1);
    }
}

The above example can be run like so:

ⓘ
$ git clone git://github.com/BurntSushi/rust-csv
$ cd rust-csv
$ cargo run --example cookbook-read-basic < examples/data/smallpop.csv

Example with Serde

This example shows how to read CSV data from stdin into your own custom struct. By default, the member names of the struct are matched with the values in the header record of your CSV data.

use std::{error::Error, io, process};

#[derive(Debug, serde::Deserialize)]
struct Record {
    city: String,
    region: String,
    country: String,
    population: Option<u64>,
}

fn example() -> Result<(), Box<dyn Error>> {
    let mut rdr = csv::Reader::from_reader(io::stdin());
    for result in rdr.deserialize() {
        // Notice that we need to provide a type hint for automatic
        // deserialization.
        let record: Record = result?;
        println!("{:?}", record);
    }
    Ok(())
}

fn main() {
    if let Err(err) = example() {
        println!("error running example: {}", err);
        process::exit(1);
    }
}

The above example can be run like so:

ⓘ
$ git clone git://github.com/BurntSushi/rust-csv
$ cd rust-csv
$ cargo run --example cookbook-read-serde < examples/data/smallpop.csv

Modules

  • cookbook
    A cookbook of examples for CSV reading and writing.
  • tutorial
    A tutorial for handling CSV data in Rust.

Structs

Enums

Functions

  • invalid_option
    A custom Serde deserializer for possibly invalid Option<T> fields.

Type Aliases

  • Result
    A type alias for Result<T, csv::Error>.