How to combine more than two generic lists in C# Zip?
c#, linq
Solution
The most obvious way for me would be to use `Zip` twice.
For example,
var results = l1.Zip(l2, (x, y) => x + y).Zip(l3, (x, y) => x + y);
would combine (add) the elements of three `List<int>` objects.
Update:
You could define a new extension method that acts like a `Zip` with three `IEnumerable`s, like so:
public static class MyFunkyExtensions
{
public static IEnumerable<TResult> ZipThree<T1, T2, T3, TResult>(
this IEnumerable<T1> source,
IEnumerable<T2> second,
IEnumerable<T3> third,
Func<T1, T2, T3, TResult> func)
{
using (var e1 = source.GetEnumerator())
using (var e2 = second.GetEnumerator())
using (var e3 = third.GetEnumerator())
{
while (e1.MoveNext() && e2.MoveNext() && e3.MoveNext())
yield return func(e1.Current, e2.Current, e3.Current);
}
}
}
The usage (in the same context as above) now becomes:
var results = l1.ZipThree(l2, l3, (x, y, z) => x + y + z);
Similarly, you three lists can now be combined with:
var results = list1.ZipThree(list2, list3, (a, b, c) => new { a, b, c });
Problem
I have three (it's possible to have more than 3-4 generic list, but in this example let 3) generic lists. ``` List<string> list1 List<string> list2 List<string> list3 ``` all lists have same number of elements (same counts). I used that for combining two lists with ZIP : ``` var result = list1.Zip(list2, (a, b) => new { test1 = f, test2 = b } ``` I used that for `foreach` statement, to avoid `foreach` each List, like ``` foreach(var item in result){ Console.WriteLine(item.test1 + " " + item.test2); } ``` How to use simmilary with Zip for three lists ? Thanks EDIT: I want like: ``` List<string> list1 = new List<string>{"test", "otherTest"}; List<string> list2 = new List<string>{"item", "otherItem"}; List<string> list3 = new List<string>{"value", "otherValue"}; ``` after ZIP (I don't know method), I want to result (in VS2010 debug mode) ``` [0] { a = {"test"}, b = {"item"}, c = {"value"} } [1] { a = {"otherTest"}, b = {"otherItem"}, c = {"otherValue"} } ``` How to do that ?