拉斯特型铸造阵列/矢量 [英] Type-casting arrays/vectors in Rust

问题描述

什么是拉斯特阵列或一种类型的媒介转换到另一种惯用的方法吗？所需的效果是

What would be the idiomatic way of converting arrays or vectors of one type to another in Rust? The desired effect is

let x = ~[0 as int, 1 as int, 2 as int];
let y = vec::map(x, |&e| { e as uint });

但我不知道，如果同样的能够在一个更加简洁时尚，类似于标量类型强制转换来实现。

but I'm not sure if the same could be achieved in a more concise fashion, similar to scalar type-casts.

我似乎在发现了锈病手动或参考的线索失败。 TIA。

I seem to fail at finding clues in the Rust manual or reference. TIA.

推荐答案

在一般情况下，你会得到最好的就是类似于你有什么（这个分配一个新的向量）：

In general, the best you are going to get is similar to what you have (this allocates a new vector):

let x = ~[0i, 1, 2];
let y = do x.map |&e| { e as uint };
// equivalently,
let y = x.map(|&e| e as uint);

尽管如此，如果你知道你的铸造事情位模式是相同的（如NEWTYPE结构给它缠上，或 UINT 间铸造的类型和 INT ），你可以做一个就地投，不会分配一个新的载体（尽管它意味着老 X 无法访问）：

Although, if you know the bit patterns of the things you are casting between are the same (e.g. a newtype struct to the type it wraps, or casting between uint and int), you can do an in-place cast, that will not allocate a new vector (although it means that the old x can not be accessed):

let x = ~[0i, 1, 2];
let y: ~[uint] = unsafe { cast::transmute(x) };

（注意，这是不安全，并可能导致坏事情发生。）

(Note that this is unsafe, and can cause Bad Things to happen.)

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