std.algorithm.remove() 复制数组项？

Question

我有一个数组，需要按索引从中删除项目。由于某种原因，它会复制数组中的其他项目以取代已删除项目的位置。这是问题的示例。

import std.stdio: writeln;
import std.algorithm: remove;

void main() {
    string[string] assocArray = [
        "firstvalue": "Number 1",
        "secondvalue": "Number 2",
        "thirdvalue": "Number 3",
        "fourthvalue": "Number 4",
        "fifthvalue": "Number 5",
        "sixthvalue": "Number 6",
    ];

    string[] assocArrayKeys = assocArray.keys(); // I know these aren't in the same order as the literal.

    writeln(assocArrayKeys);
    // ["thirdvalue", "fourthvalue", "fifthvalue", "sixthvalue", "firstvalue", "secondvalue"]

    assocArrayKeys.remove(0);
    assocArrayKeys.remove(5);

    writeln(assocArrayKeys);
    // ["fourthvalue", "fifthvalue", "sixthvalue", "firstvalue", "secondvalue", "secondvalue"]
    // It did remove them, but there are now two "secondvalue"s.
}

如有任何帮助，我们将不胜感激。

Answer 1

这是一个有点愚蠢的问题。有人指出，在文档中，它说它必须重新分配给自己。

Note that remove does not change the length of the original range directly; instead, it returns the shortened range. If its return value is not assigned to the original range, the original range will retain its original length, though its contents will have changed.

来源：https://dlang.org/library/std/algorithm/mutation/remove.html

解决方法如下：

assocArraykeys = assocArrayKeys.remove(0);
assocArrayKeys = assocArrayKeys.remove(5);

这对我来说似乎有点愚蠢和不直观，因为它在 std.algorithm.mutation 中。关键字：突变.

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