[Proposal] Parameterless SelectMany() Overload for LINQ

[JBrown526]

Add an overload to SelectMany() with no parameters to flatten nested collections:

Currently to do this, you must call:

List<List<T>> nested = [];
nested.SelectMany(i => i);

It seems to me that having to add i => i is fairly pointless, and not entirely intuitive. Instead there could be an overload that takes no selector and simply flattens the nested collections.

public static IEnumerable<TResult> SelectMany<TResult>(this IEnumerable<IEnumerable<TResult>> source)
{
    // Implementation, essentially:
    return source.SelectMany(i => i);
}

Which would subsequently be used like so:

List<List<T>> nested = [];
nested.SelectMany();

[333fred]

I believe you're looking for dotnet/runtime, not this repository. API suggestions are here.

[JBrown526]

Ah gotcha, my bad!

[colejohnson66]

See dotnet/runtime#54220.

[HaloFour]

You could also define one yourself:

public static class SelecyManyExtensions {
    public static IEnumerable<T> SelectMany<T>(this IEnumerable<IEnumerable<T>> items) {
        return items.SelectMany(i => i);
    }
}

[JBrown526]

Yep I can and have! But this was more a (poorly placed) API request as I don't think that flattening nested collections is such an exotic and uncommon piece of behaviour that it should need to be defined by a developer every time they need it or as part of a third party library.

[jnm2]

That's an interesting lens, the BCL as "containing everything that's not exotic."