d9515ad40f
Fixes #24070 or rather, fixes it even though it's already been fixed: slices are before now. But the linking is nice anyway.
38 lines
1.0 KiB
Markdown
38 lines
1.0 KiB
Markdown
% Vectors
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A *vector* is a dynamic or "growable" array, implemented as the standard
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library type [`Vec<T>`](../std/vec/) (Where `<T>` is a [Generic](./generics.md)
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statement). Vectors always allocate their data on the heap. Vectors are to
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[slices][slices] what [`String`][string] is to `&str`. You can
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create them with the `vec!` macro:
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```{rust}
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let v = vec![1, 2, 3]; // v: Vec<i32>
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```
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[slices]: primitive-types.html#slices
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[string]: strings.html
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(Notice that unlike the `println!` macro we've used in the past, we use square
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brackets `[]` with `vec!`. Rust allows you to use either in either situation,
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this is just convention.)
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There's an alternate form of `vec!` for repeating an initial value:
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```
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let v = vec![0; 10]; // ten zeroes
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```
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You can get the length of, iterate over, and subscript vectors just like
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arrays. In addition, (mutable) vectors can grow automatically:
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```{rust}
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let mut nums = vec![1, 2, 3]; // mut nums: Vec<i32>
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nums.push(4);
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println!("The length of nums is now {}", nums.len()); // Prints 4
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```
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Vectors have many more useful methods.
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