中文
devexamples

Parse CSV Records into Serde Structs

Deserialize CSV records into typed Serde structs with header mapping, numeric parsing, and an error on negative quantities.

RustData Integrity

Code

snippet
use serde::Deserialize;
use std::error::Error;
use std::io;

#[derive(Debug, Deserialize, PartialEq)]
struct InventoryRow {
    sku: String,
    quantity: u32,
    price_cents: u32,
}

fn parse_inventory(csv_data: &str) -> Result<Vec<InventoryRow>, Box<dyn Error>> {
    let mut reader = csv::ReaderBuilder::new()
        .trim(csv::Trim::All)
        .from_reader(io::Cursor::new(csv_data));

    let mut rows = Vec::new();
    for record in reader.deserialize() {
        let row: InventoryRow = record?;
        rows.push(row);
    }
    Ok(rows)
}

fn main() -> Result<(), Box<dyn Error>> {
    let data = "sku,quantity,price_cents\nA-1,5,1200\nB-2,3,800\n";
    let rows = parse_inventory(data)?;
    println!("{} rows, first={:?}", rows.len(), rows.first());
    assert_eq!(rows.len(), 2);
    assert_eq!(
        rows[0],
        InventoryRow {
            sku: "A-1".into(),
            quantity: 5,
            price_cents: 1200,
        }
    );

    let bad = "sku,quantity,price_cents\nA-1,-5,1200\n";
    assert!(parse_inventory(bad).is_err(), "negative quantity must fail");
    Ok(())
}

Related Examples