Python Morsels: Avoid "reduce" in Python

Table of contents

1. What is the functools.reduce function?
2. Performing arithmetic (a bad example)
3. A more complex example
4. Don't re-invent the wheel
5. Common reduce operations in Python
6. Try to avoid functools.reduce

What is the functools.reduce function?

The functools.reduce function looks a little bit like this:

not_seen=object()defreduce(function,iterable,default=not_seen):"""An approximation of the code for functools.reduce."""value=defaultforiteminiterable:ifvalueisnot_seen:value=itemcontinuevalue=function(value,item)returnvalue

not_seen=object()defreduce(function,iterable,default=not_seen):"""An approximation of the code for functools.reduce."""value=defaultforiteminiterable:ifvalueisnot_seen:value=itemcontinuevalue=function(value,item)returnvalue

The reduce function is a bit complex. It's best understood with an example.

Performing arithmetic (a bad example)

>>> fromfunctoolsimportreduce …