Question

我尝试编译以下代码：

extern crate rand; // 0.6
use rand::Rng;

fn main() {
    rand::thread_rng()
        .gen_ascii_chars()
        .take(10)
        .collect::<String>();
}

但是cargo build说：

warning: unused import: `rand::Rng`
 --> src/main.rs:2:5
  |
2 | use rand::Rng;
  |     ^^^^^^^^^
  |
  = note: #[warn(unused_imports)] on by default

error[E0599]: no method named `gen_ascii_chars` found for type `rand::prelude::ThreadRng` in the current scope
 --> src/main.rs:6:10
  |
6 |         .gen_ascii_chars()
  |          ^^^^^^^^^^^^^^^

Rust编译器要求我删除use rand::Rng;子句，同时抱怨没有gen_ascii_chars方法。我希望Rust只使用rand::Rng特质，而不提供这种矛盾的错误消息。我该怎么走？

Answer 1

如rand 0.5.0 docs中所述，gen_ascii_chars已过时。

从0.6.0开始，代码应为：

extern crate rand;

use rand::Rng; 
use rand::distributions::Alphanumeric;

fn main() {
    rand::thread_rng()
        .sample_iter(&Alphanumeric)
        .take(10)
        .collect::<String>(); 
}

如何通过从字母数字字符中采样来创建随机字符串？

1 个答案: