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https://github.com/ahgamut/rust-ape-example.git
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48 lines
1.6 KiB
Rust
48 lines
1.6 KiB
Rust
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// ./src/fn/closures/closure_examples/iter_find.md
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fn part0() {
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let vec1 = vec![1, 2, 3];
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let vec2 = vec![4, 5, 6];
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// `iter()` for vecs yields `&i32`.
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let mut iter = vec1.iter();
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// `into_iter()` for vecs yields `i32`.
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let mut into_iter = vec2.into_iter();
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// `iter()` for vecs yields `&i32`, and we want to reference one of its
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// items, so we have to destructure `&&i32` to `i32`
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println!("Find 2 in vec1: {:?}", iter .find(|&&x| x == 2));
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// `into_iter()` for vecs yields `i32`, and we want to reference one of
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// its items, so we have to destructure `&i32` to `i32`
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println!("Find 2 in vec2: {:?}", into_iter.find(| &x| x == 2));
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let array1 = [1, 2, 3];
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let array2 = [4, 5, 6];
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// `iter()` for arrays yields `&i32`
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println!("Find 2 in array1: {:?}", array1.iter() .find(|&&x| x == 2));
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// `into_iter()` for arrays yields `i32`
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println!("Find 2 in array2: {:?}", array2.into_iter().find(|&x| x == 2));
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}
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fn part1() {
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let vec = vec![1, 9, 3, 3, 13, 2];
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// `iter()` for vecs yields `&i32` and `position()` does not take a reference, so
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// we have to destructure `&i32` to `i32`
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let index_of_first_even_number = vec.iter().position(|&x| x % 2 == 0);
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assert_eq!(index_of_first_even_number, Some(5));
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// `into_iter()` for vecs yields `i32` and `position()` does not take a reference, so
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// we do not have to destructure
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let index_of_first_negative_number = vec.into_iter().position(|x| x < 0);
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assert_eq!(index_of_first_negative_number, None);
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}
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pub fn main() {
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part0();
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part1();
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}
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