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c2a01888e1
Some more reading required on the following: - `move_semantics` aka ownership and borrowing. - `enums` especially using with match expressions.
45 lines
1.1 KiB
Rust
45 lines
1.1 KiB
Rust
// vecs2.rs
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// A Vec of even numbers is given. Your task is to complete the loop
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// so that each number in the Vec is multiplied by 2.
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//
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// Make me pass the test!
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//
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// Execute `rustlings hint vecs2` or use the `hint` watch subcommand for a hint.
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fn vec_loop(mut v: Vec<i32>) -> Vec<i32> {
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for i in v.iter_mut() {
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// Fill this up so that each element `i` in Vec `v` is multiplied by 2.
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*i *= 2;
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}
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return v;
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}
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fn vec_map(v: &Vec<i32>) -> Vec<i32> {
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v.iter().map(|num| {
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// Instead of mutating the Vec as above, we can just return the new number!
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return num * 2;
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}).collect()
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn test_vec_loop() {
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let v: Vec<i32> = (1..).filter(|x| x % 2 == 0).take(5).collect();
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let ans = vec_loop(v.clone());
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assert_eq!(ans, v.iter().map(|x| x * 2).collect::<Vec<i32>>());
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}
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#[test]
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fn test_vec_map() {
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let v: Vec<i32> = (1..).filter(|x| x % 2 == 0).take(5).collect();
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let ans = vec_map(&v);
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assert_eq!(ans, v.iter().map(|x| x * 2).collect::<Vec<i32>>());
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}
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}
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