# Iterator::find

`Iterator::find` is a function which when passed an iterator, will return the first element which satisfies the predicate as an `Option`. Its signature:

    pub trait Iterator {
        // The type being iterated over.
        type Item;

        // `find` takes `&mut self` meaning the caller may be borrowed
        // and modified, but not consumed.
        fn find<P>(&mut self, predicate: P) -> Option<Self::Item> where
            // `FnMut` meaning any captured variable may at most be
            // modified, not consumed. `&Self::Item` states it takes
            // arguments to the closure by reference.
            P: FnMut(&Self::Item) -> bool {}
    }

    fn main() {
        let vec1 = vec![1, 2, 3];
        let vec2 = vec![4, 5, 6];

        // `iter()` for vecs yields `&i32`.
        let mut iter = vec1.iter();
        // `into_iter()` for vecs yields `i32`.
        let mut into_iter = vec2.into_iter();

        // A reference to what is yielded is `&&i32`. Destructure to `i32`.
        println!("Find 2 in vec1: {:?}", iter     .find(|&&x| x == 2));
        // A reference to what is yielded is `&i32`. Destructure to `i32`.
        println!("Find 2 in vec2: {:?}", into_iter.find(| &x| x == 2));

        let array1 = [1, 2, 3];
        let array2 = [4, 5, 6];

        // `iter()` for arrays yields `&i32`
        println!("Find 2 in array1: {:?}", array1.iter()     .find(|&&x| x == 2));
        // `into_iter()` for arrays unusually yields `&i32`
        println!("Find 2 in array2: {:?}", array2.into_iter().find(|&&x| x == 2));
    }

### See also:

`std::iter::Iterator::find`