直接来自`await`的AddRange

Question

I am currently returning a list of lists ( List<List<string>> ) from await getWorlds() and right now I am looping through each one of them, and getting the first entry in each list.

I just wonder if there is another way I can quickly add all of them directly into Worlds with .AddRange or something?

Here is my code:

var worlds = await getWorlds();
foreach (var w in worlds)
{
    Worlds.Add(w[0]);
}

Any way to shorten this to something smaller? Like Worlds = worlds.AddRange([0]); or something? I just want to get the first entry [0] and add each one to the Worlds . I'm just looking to see if there's a cleaner way of writing my code. I have not managed to find any example.

Answer 1

You can do this:

var worlds = await getWorlds();
Worlds.AddRange(worlds.Select(w => w[0]));

Though I don't see why the foreach was so bad.

Answer 2

This is not quite what you're looking for, but you could do this to add all instances of items in all the sub-lists too, rather than just the first one.. (this will flatten the list into a single list of items)

var worlds = await getWorlds();
Worlds.AddRange(worlds.SelectMany(w=>w));