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| author | cyqsimon <28627918+cyqsimon@users.noreply.github.com> | 2022-02-12 12:19:03 +0800 |
|---|---|---|
| committer | cyqsimon <28627918+cyqsimon@users.noreply.github.com> | 2022-02-12 12:19:03 +0800 |
| commit | adfac00f458c7b68efb759335a804949d2f64d8b (patch) | |
| tree | 625ec93f42541c777e461e84f39374abd150b5d4 | |
| parent | 7eaecc6508149da3a0e76982f1259f5bf3cf54a8 (diff) | |
| download | rust-adfac00f458c7b68efb759335a804949d2f64d8b.tar.gz rust-adfac00f458c7b68efb759335a804949d2f64d8b.zip | |
`Result::and_then`: show type conversion
| -rw-r--r-- | library/core/src/result.rs | 11 |
1 files changed, 5 insertions, 6 deletions
diff --git a/library/core/src/result.rs b/library/core/src/result.rs index d6a0c7dc292..334a8990787 100644 --- a/library/core/src/result.rs +++ b/library/core/src/result.rs @@ -1282,14 +1282,13 @@ impl<T, E> Result<T, E> { /// # Examples /// /// ``` - /// fn sq(x: u32) -> Result<u32, &'static str> { - /// x.checked_mul(x).ok_or("overflowed") + /// fn sq_then_to_string(x: u32) -> Result<String, &'static str> { + /// x.checked_mul(x).map(|sq| sq.to_string()).ok_or("overflowed") /// } /// - /// assert_eq!(Ok(2).and_then(sq), Ok(4)); - /// assert_eq!(Ok(1_000_000).and_then(sq), Err("overflowed")); - /// assert_eq!(Err("not a number").and_then(sq), Err("not a number")); - + /// assert_eq!(Ok(2).and_then(sq_then_to_string), Ok(4.to_string())); + /// assert_eq!(Ok(1_000_000).and_then(sq_then_to_string), Err("overflowed")); + /// assert_eq!(Err("not a number").and_then(sq_then_to_string), Err("not a number")); /// ``` /// /// Often used to chain fallible operations that may return [`Err`]. |
