Question

Let’s say I have a closure:

def increment = {value, step ->
   value + step 
}

Now I want to loop over every item of my integers collection, increment it with 5, and save new elements to a new collection:

def numbers = [1..10]
def biggerNumbers = numbers.collect {
      it + 5
} 

And now I want to achieve the same result but by means of using increment closure. How can I do this?

Should be something like this (wrong code below):

def biggerNumbers = numbers.collect increment(it, 5) //what's the correct name of 'it'??

Answer 1

The solution to your problem would be nesting your call of increment in a closure:

def biggerNumbers = numbers.collect {increment(it, 5)}

If you wanted to pass a premade closure to the collect you should have made it compatible with collect – accepting a single parameter that is:

def incrementByFive = {it + 5}
def biggerNumbers = numbers.collect incrementByFive