Modern Python Standard Library Cookbook

How to do it...

The steps for this recipe are as follows:

1. The most simple example of reduction is summing all items in an iterable:

>>> values = [ 1, 2, 3, 4, 5 ]

2. This is something that can easily be done by sum, but for the sake of this example, we will use reduce:

>>> import functools, operator
>>> functools.reduce(operator.add, values)
15

3. If instead of having a single final result, you want to keep the results of the intermediate steps, you can use accumulate:

>>> import itertools
>>> list(itertools.accumulate(values, operator.add))
[1, 3, 6, 10, 15]