Day 08 - Option与Result

Option

fn find_user(id: u32) -> Option<String> {
    if id == 1 {
        Some(String::from("alice"))
    } else {
        None
    }
}

// 使用
match find_user(1) {
    Some(name) => println!("Found: {}", name),
    None => println!("Not found"),
}

Result

use std::fs::File;

fn read_file(path: &str) -> Result<String, std::io::Error> {
    let mut content = String::new();
    File::open(path)?. .read_to_string(&mut content)?;
    Ok(content)
}

问号运算符

fn read_file(path: &str) -> Result<String, std::io::Error> {
    let mut file = File::open(path)?;  // ?自动传播错误
    let mut content = String::new();
    file.read_to_string(&mut content)?;
    Ok(content)
}

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📅 学习进度

Day	主题	状态
01-07	基础	✅
08	Option与Result	✅
09	泛型	⬜

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本文为Rust 30天学习计划第8天内容

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