feat(vec): update vec exercises
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@ -2,7 +2,7 @@
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// Your task is to create a `Vec` which holds the exact same elements
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// as in the array `a`.
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// Make me compile and pass the test!
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// Execute the command `rustlings hint vec1` if you need hints.
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// Execute `rustlings hint vec1` or use the `hint` watch subcommand for a hint.
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// I AM NOT DONE
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@ -4,8 +4,7 @@
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//
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// Make me pass the test!
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//
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// Execute the command `rustlings hint vec2` if you need
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// hints.
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// Execute `rustlings hint vec2` or use the `hint` watch subcommand for a hint.
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// I AM NOT DONE
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@ -13,12 +12,21 @@ fn vec_loop(mut v: Vec<i32>) -> Vec<i32> {
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for i in v.iter_mut() {
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// TODO: Fill this up so that each element in the Vec `v` is
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// multiplied by 2.
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???
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}
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// At this point, `v` should be equal to [4, 8, 12, 16, 20].
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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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// TODO: Do the same thing as above - but instead of mutating the
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// Vec, you can just return the new number!
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???
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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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@ -30,4 +38,12 @@ mod tests {
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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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12
info.toml
12
info.toml
@ -260,9 +260,15 @@ name = "vec2"
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path = "exercises/collections/vec2.rs"
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mode = "test"
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hint = """
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Hint 1: `i` is each element from the Vec as they are being iterated.
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Can you try multiplying this?
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Hint 2: Check the suggestion from the compiler error ;)
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Hint 1: `i` is each element from the Vec as they are being iterated. Can you try
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multiplying this?
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Hint 2: For the first function, there's a way to directly access the numbers stored
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in the Vec, using the * dereference operator. You can both access and write to the
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number that way.
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After you've completed both functions, decide for yourself which approach you like
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better. What do you think is the more commonly used pattern under Rust developers?
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"""
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# MOVE SEMANTICS
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