Adds method that will batch the values in a list into a new list containing batches of items

batch-feature.groovy

Object.metaClass.partition = { partitionSize ->
  def result = delegate.inject([[]]) { partitioned, it ->
    if(partitioned.last().size() == partitionSize) { 
      partitioned << [it]
    } else { 
      partitioned.last() << it
    }
    partitioned
  }
  result?.last().size() == 0 ? [] : result
}

assert [1, 2, 3, 4, 5].partition(1) == [[1], [2], [3], [4], [5]]
assert [1, 2, 3].partition(2) == [[1, 2], [3]]
assert [1, 2, 3].partition(5) == [[1, 2, 3]]
assert [].partition(100) == []

I like that this gives you an easy to read way to map a list, ie;

assert [ a:10, b:20, c:30 ] == [ 'a', 10, 'b', 20, 'c', 30 ].partition( 2 ).collectEntries { it }

Nice, I hadn't even thought of that. My use case is for creating batches of data to be sent into a remote service. Partition that was used on the stackoverflow page is probably a name that is more in line with what it actually does.