如何通过一个步骤获取列表中项目的索引? [英] How can I get the index of an item in a list in a single step?

问题描述

如何在不循环的情况下找到列表中项目的索引?

目前这看起来不太好 - 在列表中搜索相同的项目两次，只是为了获取索引:

var oProp = something;int theThingIActuallyAmInterestedIn = myList.IndexOf(myList.Single(i => i.Prop == oProp));

解决方案

List.FindIndex 方法:

int index = myList.FindIndex(a => a.Prop == oProp);

<块引用>

此方法执行线性搜索；因此，这种方法是一种O(n) 操作，其中 n 是 Count.

如果没有找到，返回-1

How can I find the index of an item in a list without looping through it?

Currently this doesn't look very nice - searching through the list for the same item twice, just to get the index:

var oProp = something;

int theThingIActuallyAmInterestedIn = myList.IndexOf(myList.Single(i => i.Prop == oProp));

解决方案

How about the List.FindIndex Method:

int index = myList.FindIndex(a => a.Prop == oProp);

This method performs a linear search; therefore, this method is an O(n) operation, where n is Count.

If the item is not found, it will return -1

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