Sorting list by an attribute that can be None

Question

I\'m trying to sort a list of objects using

my_list.sort(key=operator.attrgetter(attr_name))

but if any of the list items has attr = None

Answer 1

For a general solution, you can define an object that compares less than any other object:

from functools import total_ordering

@total_ordering
class MinType(object):
    def __le__(self, other):
        return True

    def __eq__(self, other):
        return (self is other)

Min = MinType()

Then use a sort key that substitutes Min for any None values in the list

mylist.sort(key=lambda x: Min if x is None else x)