如何从元组(Option<&str>，Option<&str>)转换为元组(Option<String>，Option<String>)？

Question

我想从这件事中得到：

let a: Option<&str> = Some("foo");
let b: Option<String> = a.map(|s| s.to_string());

以元组形式：

let c: (Option<&str>, Option<&str>) = (Some("bar"), Some("baz"));
let d: (Option<String>, Option<String>) = c.map(|s| (s.0.to_string(), s.1.to_string()));

7 |     let d: (Option<String>, Option<String>) = c.map(|s| (s.0.to_string(), s.1.to_string()));
  |                                                 ^^^ `(Option<&str>, Option<&str>)` is not an iterator
  |
  = note: the following trait bounds were not satisfied:
          `(Option<&str>, Option<&str>): Iterator`
          which is required by `&mut (Option<&str>, Option<&str>): Iterator

如何使用rust 1.61或更新将可选字符串片的元组转换为可选字符串的元组？

操场链接

Answer 1

就像你有两个变量时那样做吧：

let c = (Some("bar"), Some("baz"));
let d = (c.0.map(|s| s.to_string()), c.1.map(|s| s.to_string()));