C#从类列表中提取字段列表 [英] C# Extract list of fields from list of class

问题描述

我有一个特定类的元素列表.此类包含一个字段.

I've got a list of elements of a certain class. This class contains a field.

class Foo {public int i;}
List<Foo> list;

我想将列表中所有项目的字段提取到新列表中.

I'd like to extract the field from all items in the list into a new list.

List<int> result = list.ExtractField (e => e.i); // imaginary

肯定有多种方法可以执行此操作，但是我还没有找到一个美观的解决方案.我认为linq可能会有所帮助，但我不确定效果如何.

There are surely multiple ways to do that, but I did not find a nice-looking solution yet. I figured linq might help, but I was not sure how exactly.

推荐答案

刚刚:

List<int> result = list.Select(e => e.i).ToList();

或

List<int> result = list.ConvertAll(e => e.i);

后者效率更高(因为它知道开始时的最终大小)，但仅适用于列表和数组，而不适用于任何任意序列.

The latter is more efficient (because it knows the final size to start with), but will only work for lists and arrays rather than any arbitrary sequence.

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