F#'s underscore: why not just create a variable name?

Question

Reading about F# today and I'm not clear on one thing:

From: http://msdn.microsoft.com/en-us/library/dd233200.aspx

you need only one element of the tuple, the wildcard character (the underscore) can be used to avoid creating a new name for a variable that you do not need

let (a, _) = (1, 2)

I can't think of a time that I've been in this situation. Why would you avoid creating a variable name?

Answer 1

Because you don't need the value. I use this often. It documents the fact that a value is unused and saves naming variables unused, dummy, etc. Great feature if you ask me.