This Question pertains to a pre-release version of Rust.
This younger Question is similar.如何將char轉換爲字符串?
我試圖通過io::println
功能
fn main() {
io::println('c');
}
打印一個符號,但我得到了一個錯誤:
$ rustc pdst.rs
pdst.rs:2:16: 2:19 error: mismatched types: expected `&str` but found `char` (expected &str but found char)
pdst.rs:2 io::println('c');
^~~
error: aborting due to previous error
如何字符轉換爲字符串?
UPDATE
直接類型轉換不起作用:
let text:str = 'c';
let text:&str = 'c';
let text:@str = 'c';
let text:~str = 'c';
它返回:
pdst.rs:7:13: 7:16 error: bare `str` is not a type
pdst.rs:7 let text:str = 'c';
^~~
pdst.rs:7:19: 7:22 error: mismatched types: expected `~str` but found `char` (expected ~str but found char)
pdst.rs:7 let text:str = 'c';
^~~
pdst.rs:8:20: 8:23 error: mismatched types: expected `&str` but found `char` (expected &str but found char)
pdst.rs:8 let text:&str = 'c';
^~~
pdst.rs:9:20: 9:23 error: mismatched types: expected `@str` but found `char` (expected @str but found char)
pdst.rs:9 let text:@str = 'c';
^~~
pdst.rs:10:20: 10:23 error: mismatched types: expected `~str` but found `char` (expected ~str but found char)
pdst.rs:10 let text:~str = 'c';
^~~
error: aborting due to 5 previous errors
這似乎沒有明確說明,但它是真實的,因爲char的實現顯示和顯示實現需要to_string,但是您不會從Display文檔知道這一點,這是記錄在ToString特徵上的。這不是很好。 https://doc.rust-lang.org/std/string/trait.ToString.html – 2017-02-09 23:41:22