diff options
| -rw-r--r-- | library/core/src/option.rs | 21 |
1 files changed, 15 insertions, 6 deletions
diff --git a/library/core/src/option.rs b/library/core/src/option.rs index ec04692d3e0..f8758056db9 100644 --- a/library/core/src/option.rs +++ b/library/core/src/option.rs @@ -1207,13 +1207,22 @@ impl<T> Option<T> { /// # Examples /// /// ``` - /// fn sq(x: u32) -> Option<u32> { Some(x * x) } - /// fn nope(_: u32) -> Option<u32> { None } + /// fn squared_string(x: u32) -> Option<String> { Some((x * x).to_string()) } /// - /// assert_eq!(Some(2).and_then(sq).and_then(sq), Some(16)); - /// assert_eq!(Some(2).and_then(sq).and_then(nope), None); - /// assert_eq!(Some(2).and_then(nope).and_then(sq), None); - /// assert_eq!(None.and_then(sq).and_then(sq), None); + /// assert_eq!(Some(2).and_then(squared_string), Some(4.to_string())); + /// assert_eq!(None.and_then(squared_string), None); + /// ``` + /// + /// Often used to chain fallible operations that may return [`None`]. + /// + /// ``` + /// let arr_2d = [["A1", "A2"], ["B1", "B2"]]; + /// + /// let item_0_1 = arr_2d.get(0).and_then(|row| row.get(1)); + /// assert_eq!(item_0_1, Some(&"A2")); + /// + /// let item_2_0 = arr_2d.get(2).and_then(|row| row.get(0)); + /// assert_eq!(item_2_0, None); /// ``` #[inline] #[stable(feature = "rust1", since = "1.0.0")] |