Comments on: More missing LINQ operators

By: Joshua Alden Lewis

Joshua Alden Lewis — Fri, 05 Apr 2013 17:35:00 +0000

I like that Alternate extension a lot. Have you thought about a version that would multiple list to be interwoven in an alternating fashion as opposed to just 2.

By: bogardj

bogardj — Fri, 30 Oct 2009 12:35:57 +0000

@Everett

That’s good too! I thought of Zip, but that was already taken I think “Splice” might be a good term too?

By: Everett Muniz

Everett Muniz — Fri, 30 Oct 2009 02:45:46 +0000

Thanks for sharing this. This is pretty incidental but I wonder if a clearer, more accurate name for Alternate would be Interlace.

By: Jarrett Meyer

Jarrett Meyer — Fri, 16 Oct 2009 17:20:24 +0000

I find myself constantly wanting all of the array operations from Python to be available in .NET (without rewriting them myself).

By: bogardj

bogardj — Fri, 16 Oct 2009 15:45:59 +0000

@Will, @Diogo

The real-life example is a split-join scenario, where the other joined piece is a list of custom items. It’s a template thing, transforming:

“Hello [blank], today is [blank]” to “Hello Joe, today is Thursday”

By: Will

Will — Fri, 16 Oct 2009 15:04:09 +0000

Alternate:
Interesting, yet the example doesn’t seem like a good fit. As Diogo pointed out, you can simply use String.Join if the alternating value never changes.

Append / Prepend
I really like using the “params” keyword in situations like this. It allows me to call on a method more naturally and the compiler composes the collection (array) for me. Plus, in these examples, you would be able to append or prepend multiple values.

e.g.
public static IEnumerable Append( this IEnumerable source, params TSource[] elements )
{
return source.Concat( elements );
}

var start = new[] { 1, 2, 3 };
var result = new[] { 1, 2, 3, 4, 5 };
start.Append( 4, 5 ).ShouldHaveSameElements( result );

However, I’ve never gone this far. I’ve been content with Joshua’s suggestion of new[]{x}.

By: Diogo Mafra

Diogo Mafra — Fri, 16 Oct 2009 13:24:58 +0000

In the first example you could use String.Join:
String.Join(” “, source)

I would like to have an extension method to verify if a string is null or empty ignoring spaces:
(name == null || name.Trim().Length == 0)

By: bogardj

bogardj — Fri, 16 Oct 2009 13:12:04 +0000

@Josh

Ha, yeah we use that way too especially in the overloads that take collections, but we just want to work with a single item. Concat, Union, Except, etc etc.

By: Joshua Flanagan

Joshua Flanagan — Fri, 16 Oct 2009 12:18:33 +0000

I can see why you would hate the Enumerable.Repeat syntax, but not sure what would drive you to use it (except counting clock cycles).

var oneToFour = ints.Concat(new[]{4});

Not as pretty as Append, but definitely an improvement over Enumerable.Repeat, in my opinion.

By: Richard Dingwall

Richard Dingwall — Fri, 16 Oct 2009 09:30:43 +0000

Nice, someone should get a project going for extra operators like these. Traverse() is another favourite of mine for flattening recursive hierarchies: http://social.msdn.microsoft.com/forums/en-US/linqprojectgeneral/thread/fe3d441d-1e49-4855-8ae8-60068b3ef741/