如何从序列中间剪切一些元素？

Question

Is it possible using LINQ expression to skip some elements from the middle of the sequence? I want to Take N elements, then Skip M elements, then take the rest of the sequence. I know that I can write my own function for that but I wonder is it possible to do it using only built-in functions?

Answer 1

One way is to use the index:

sequence.Select((value, index) => new {value, index})
.Where(x => x.index < startOfRange || x.index > endOfRange)
.Select(x.value);

Or, even simpler: (can't believe I didn't think of that the first time)

sequence.Where((value, index) => index < startOfRange || index > endOfRange)

Answer 2

int n = 5;
int m = 10;
int k = n+m;
var seq = Enumerable.Range(100, 20).Where((p,i) => i<=n || i>= k)));

// the output is 100,101,102,103,104,105,115,116,117,118,119

Answer 3

这可以通过Skip()和Take()来完成，你只需要使用Concat() 。

sequence.Take(N).Concat(sequence.Skip(N + M));

Answer 4

myList.Where((o, i) => i <= startSkip || i >= endSkip);