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 listWritten with Groovy 3.0.1.