Modern Python Standard Library Cookbook

How it works...

The bisect module uses dichotomic searching to look for the point of insertion of an element in a sorted container.

If an element exists in the array, its insertion position is exactly where the element is (as it should go exactly where it is):

>>> values = [ 1, 3, 5, 7 ]
>>> bisect.bisect_left(values, 5)
2

If the element is missing, it will return the position of the next, immediately bigger element:

>>> bisect.bisect_left(values, 4)
2

This means we will get a position even for elements that do not exist in our container. That's why we compare the element at the returned position with the element that we were looking for. If the two are different, it means that the nearest element was returned and so the element itself was ...