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clarify that find returns first match

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the example for `find` was misleading in that it fails to mention the result is either `None` or `Some` containing only the first match. Further confusing the issue is the `println!` statement, "We got some numbers!"
This commit is contained in:
David Elliott 2015-09-26 10:36:37 -07:00
parent 2e88c36ebc
commit ded2370a74
1 changed files with 5 additions and 4 deletions
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src/doc/trpl/iterators.md
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@ -150,15 +150,16 @@ let greater_than_forty_two = (0..100)
.find(|x| *x > 42);
match greater_than_forty_two {
Some(_) => println!("We got some numbers!"),
None => println!("No numbers found :("),
Some(_) => println!("Found a match!"),
None => println!("No match found :("),
}
```
`find` takes a closure, and works on a reference to each element of an
iterator. This closure returns `true` if the element is the element we're
looking for, and `false` otherwise. Because we might not find a matching
element, `find` returns an `Option` rather than the element itself.
looking for, and `false` otherwise. `find` returns the first element satisfying
the specified predicate. Because we might not find a matching element, `find`
returns an `Option` rather than the element itself.
Another important consumer is `fold`. Here's what it looks like: