如何使用Lambda过滤地图? [英] How to filter a map using Lambda?

问题描述

我有一个地图变量:

var bitmapDepths:Map<BitmapData, Int>;

我需要删除所有值为0的键，我对此进行了尝试:

What I need is to remove all keys with value of 0, I tried this:

bitmapDepths= Lambda.filter(Lambda.list(bitmapDepths.keys), function(v) { return (v > 0); });

因此，我使用Lambda.list遍历Lambda内的bitmapDepths.keys，但出现此错误:

So, I used Lambda.list to iterate on bitmapDepths.keys inside Lambda, but I get this error:

Void -> Iterator<flash.display.BitmapData> should be Iterable<Unknown<0>>

我尝试了Lambda.array来对bitmapDepths.keys进行迭代，但是我遇到了同样的错误，那么谁可以处理呢?使用Lambda删除基于值的键?

I tried Lambda.array to iterate on bitmapDepths.keys, I got the same error, so who can handle this? to remove keys based on values using Lambda?

推荐答案

请勿使用Lambda.这是Haxe 1中添加的一类.在Haxe 3中，对于循环/理解几乎总是更好的选择.

Don't use Lambda. It's a class that has been added in Haxe 1. In Haxe 3, for loops/comprehensions are almost always the better choice.

要删除适当的键，请执行以下操作:

To remove the keys in place:

for (k in bitmapDepths.keys()) if (k == 0) bitmapDepths.remove(k);

要构建新地图:

bitmapDepths = [for (k in bitmapDepths.keys()) if (k != 0) k => bitmapDepths.get(k)];

它不仅更短，而且具有更好的运行时性能.

Not only is it shorter, it also has better runtime performance.

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