Would be good to have a new collections method for "partition"

Here's a description of how the method works in Ruby:
Returns two arrays, the first containing the elements of enum for which the block evaluates to true, the second containing the rest.

So it's a bit like a filter/reject combo.

If others are interested and I get time then I'll have a go at implementing but it won't be for a few weeks at least but I thought I would put the idea here in case someone else has time