Split collection into sub collections in Groovy

Question

I have an array containing an unknown number of items that I would like to split into separate arrays so that each separate array contains no more than 4 items. What is the

Answer 1

We had this here: How to split a list into equal sized lists in Groovy?

I came up with this:

List.metaClass.partition = { size ->
  def rslt = delegate.inject( [ [] ] ) { ret, elem ->
    ( ret.last() << elem ).size() >= size ? ret << [] : ret
  }
  !rslt.last() ? rslt[ 0..-2 ] : rslt
}

def list = [1, 2, 3, 4, 5, 6].partition( 4 )

Which should give you:

[ [ 1, 2, 3, 4 ], [ 5, 6 ] ]

Update!

With Groovy 1.8.6+ you can use list.collate( 4 ) to get the same result