Groovy contains lots of little gems that just make live easier and our code more expressive. Groovy 3 doesn’t disappoint by adding some nice syntax additions. For example we can now use !in to check if an item is not in a collection, opposed to in that checks if an item is in a collection.

In the following example we use !in:

def list = ['Groovy', 3, 'is', 'awesome', '!']

// New Groovy 3 syntax to check item
// is NOT in a collection.
assert 'Java' !in list

// Old syntax.
assert !('Java' in list)

// Just to show in still works.
assert 'Groovy' in list

Written with Groovy 3.0.1.