How can I join strings from one List into another one? [closed]

Answer 1

Here is how you can do it with LINQ:

var result =
    Names
        .Select((item, index) => new {Item = item, Index = index})
        .GroupBy(x => x.Index / 500)
        .Select(g => string.Join(",", g.Select(x => x.Item)))
        .ToList();

First, for each item, you select the item it self along with its index. Then you group these items by index / 500 which means that each 500 items will be grouped together.

Then you use string.Join to join the 500 strings in each group together.