Rust 中的字符串

创建

// 字符串字面量, 类型为: &str, 从定义到整个程序的结束一直存在
let s1 = "hello world";

// 创建一个空字符串对象
let s2 = String::new();
// 从一个字符串字面量创建一个字符串对象
let s3 = String::from(s1);

处理函数

获取字符串的长度：len()

// 获取字符串长度
let s1 = "hello world";
let s2 = String::from(s1);
println!("s1.len = {}, s2.len = {}", s1.len(), s2.len());

//> s1.len = 11, s2.len = 11

获取字符串对象的字面量：as_str()

let s1 = "hello world";
let s2 = String::from(s1);
println!("s2: {}", s2.as_str());

//> s2: hello world

追加一个字符串字面量到字符串对象：push_str()

let mut s1 = String::new();
s1.push_str("hello");
s1.push_str(" world");
println!("s1: {}", s1);

//> s1: hello world

追加一个字符到字符串对象：push()

let mut s1 = String::new();
s1.push('O');
s1.push('k');
println!("s1: {}", s1);

//> s1: Ok

去除字符串首尾的空白字符：trim()

let s1 = String::from("  \r\nhello, world!  \r\n ");
let s2 = s1.trim();
println!("s1.len: {}, s2.len: {}", s1.len(), s2.len());

//> s1.len: 22, s2.len: 13

字符串分割（返回一个分割后的迭代器）：split()

let s1 = String::from("hello,world,!!!");
for s in s1.split(',') {
    println!("{}", s);
}

/*>
hello
world
!!!
*/

获取字符串中的每一个字符：chars()

let s1 = String::from("hello");
for c in s1.chars() {
    println!("{}", c);
}

/*>
h
e
l
l
o
*/

字符串的拼接：add() ，+

• 使用add()

use std::ops::Add;

let s1 = String::from("hello");
let s2 = s1.add(" world");
println!("{}", s2);

//> hello world

• 使用+

let s1 = String::from("hello");
let s2 = String::from(" world");
let s3 = s1 + &s2;
println!("{}", s3);

//> hello world