如何按索引对项目进行分组？ C＃LINQ

假设我有

var input = new int[] { 0, 1, 2, 3, 4, 5 }; 

如何将它们分组成对？

 var output = new int[][] { new int[] { 0, 1 }, new int[] { 2, 3 }, new int[] { 4, 5 } }; 

最好使用LINQ

Answer 1

 input .Select((value, index) => new { PairNum = index / 2, value }) .GroupBy(pair => pair.PairNum) .Select(grp => grp.Select(g => g.value).ToArray()) .ToArray() 

Answer 2

可能不适用于您，但您可以在C＃4.0中使用新的Zip方法

 var input = new int[] { 0, 1, 2, 3, 4, 5 }; IEnumerable evens = input.Where((element, index) => index % 2 == 0); IEnumerable odds = input.Where((element, index) => index % 2 == 1); var results = evens.Zip(odds, (e, o) => new[] { e, o }).ToArray();
var input = new int[] { 0, 1, 2, 3, 4, 5 }; IEnumerable evens = input.Where((element, index) => index % 2 == 0); IEnumerable odds = input.Where((element, index) => index % 2 == 1); var results = evens.Zip(odds, (e, o) => new[] { e, o }).ToArray(); 

Answer 3

 var input = new int[] { 0, 1, 2, 3, 4, 5 }; int i = 0; var output = input.GroupBy(item => i++ / 2); 

Answer 4

 var indexedNumbers = input.Select((number, index) => new { Index = index, Number = number }); var pairs = from indexedNumber in indexedNumbers group indexedNumber by indexedNumber.Index / 2 into indexedNumberPair select indexedNumberPair.Select(indexedNumber => indexedNumber.Number); var arrays = pairs.Select(pair => pair.ToArray()).ToArray(); 

Answer 5

使用ToLookup方法：

 input .Select((number, index) => new { index , number}) .ToLookup(_ => _.index / 2, _ => _.number) .Select(_ => _.ToArray()) .ToArray(); 

使用Zip方法：

 input .Zip(input.Skip(1), (_, __) => new[] {_, __}) .Where((_, index) => index % 2 == 0) .ToArray();