rust/rustlings
1
0
Fork 0
mirror of https://github.com/rust-lang/rustlings.git synced 2025-10-08 23:02:03 +02:00
Code Issues Releases Activity

Merge pull request #2294 from senekor/senekor/qxykzqyxnnwy

Browse Source 
Remove use of `map` in early vecs2 exercise
This commit is contained in:
Mo Bitar
2025-09-25 16:55:36 +02:00
committed by GitHub
parent 1955313362 d8f4b06c91
commit f80fbca12e
4 changed files with 5 additions and 74 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
CHANGELOG.md
View File

@@ -1,5 +1,9 @@
## Unreleased
### Changed
- `vecs2`: Removed the use of `map` and `collect`, which are only taught later.
## 6.5.0 (2025-08-21)
### Added

34
exercises/05_vecs/vecs2.rs
View File

@@ -9,26 +9,6 @@ fn vec_loop(input: &[i32]) -> Vec<i32> {
output
}
fn vec_map_example(input: &[i32]) -> Vec<i32> {
// An example of collecting a vector after mapping.
// We map each element of the `input` slice to its value plus 1.
// If the input is `[1, 2, 3]`, the output is `[2, 3, 4]`.
input.iter().map(|element| element + 1).collect()
}
fn vec_map(input: &[i32]) -> Vec<i32> {
// TODO: Here, we also want to multiply each element in the `input` slice
// by 2, but with iterator mapping instead of manually pushing into an empty
// vector.
// See the example in the function `vec_map_example` above.
input
.iter()
.map(|element| {
// ???
})
.collect()
}
fn main() {
// You can optionally experiment here.
}
@@ -43,18 +23,4 @@ mod tests {
let ans = vec_loop(&input);
assert_eq!(ans, [4, 8, 12, 16, 20]);
}
#[test]
fn test_vec_map_example() {
let input = [1, 2, 3];
let ans = vec_map_example(&input);
assert_eq!(ans, [2, 3, 4]);
}
#[test]
fn test_vec_map() {
let input = [2, 4, 6, 8, 10];
let ans = vec_map(&input);
assert_eq!(ans, [4, 8, 12, 16, 20]);
}
}

11
rustlings-macros/info.toml
View File

@@ -318,16 +318,7 @@ of the Rust book to learn more."""
name = "vecs2"
dir = "05_vecs"
hint = """
In the first function, we create an empty vector and want to push new elements
to it.
In the second function, we map the values of the input and collect them into
a vector.
After you've completed both functions, decide for yourself which approach you
like better.
What do you think is the more commonly used pattern under Rust developers?"""
Use the `.push()` method on the vector to push new elements to it."""
# MOVE SEMANTICS

30
solutions/05_vecs/vecs2.rs
View File

@@ -8,22 +8,6 @@ fn vec_loop(input: &[i32]) -> Vec<i32> {
output
}
fn vec_map_example(input: &[i32]) -> Vec<i32> {
// An example of collecting a vector after mapping.
// We map each element of the `input` slice to its value plus 1.
// If the input is `[1, 2, 3]`, the output is `[2, 3, 4]`.
input.iter().map(|element| element + 1).collect()
}
fn vec_map(input: &[i32]) -> Vec<i32> {
// We will dive deeper into iterators, but for now, this is all what you
// had to do!
// Advanced note: This method is more efficient because it automatically
// preallocates enough capacity. This can be done manually in `vec_loop`
// using `Vec::with_capacity(input.len())` instead of `Vec::new()`.
input.iter().map(|element| 2 * element).collect()
}
fn main() {
// You can optionally experiment here.
}
@@ -38,18 +22,4 @@ mod tests {
let ans = vec_loop(&input);
assert_eq!(ans, [4, 8, 12, 16, 20]);
}
#[test]
fn test_vec_map_example() {
let input = [1, 2, 3];
let ans = vec_map_example(&input);
assert_eq!(ans, [2, 3, 4]);
}
#[test]
fn test_vec_map() {
let input = [2, 4, 6, 8, 10];
let ans = vec_map(&input);
assert_eq!(ans, [4, 8, 12, 16, 20]);
}
}