GDScript has a custom iterator protocol which enables looping over objects using the standard for loop.

itertools provides several custom iterators so you don't have to reinvent the wheel yourself. Examples of provided iterators include:

• Iterators to loop over slices of arrays and strings
• Iterator version of range()
• filter() and map() iterators
• zip() and enumerate()
• Generators like integers() which can provide an infinite stream of integers
• Generators like product(...) which produces combinations of other iterators
• list() to easily turn an iterator back into a GDScript array.

Documentation

The full list of iterators is documented in the Github README.md. To see how to use these iterators, either look at the provided unit tests or read about Python's itertools, which served as the template for this addon.