Understanding how to create a heap in Python

Question

The collections.Count.most_common function in Python uses the heapq module to return the count of the most common word in a file, for instance.

I have traced through the heapq.py file, but I'm having a bit of trouble understanding how a heap is created/updated with respect to words let's say.

So, I think the best way for me to understand it, is to figure out how to create a heap from scratch.

Can someone provide a pseudocode for creating a heap that would represent word count?

Answer 1

In Python 2.X and 3.x, heaps are supported through an importable library, heapq. It supplies numerous functions to work with the heap data structure modelled in a Python list. Example:

>>> from heapq import heappush, heappop >>> heap = [] >>> data = [1, 3, 5, 7, 9, 2, 4, 6, 8, 0] >>> for item in data:         heappush(heap, item)  >>> ordered = [] >>> while heap:         ordered.append(heappop(heap))  >>> ordered [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] >>> data.sort() >>> data == ordered True 

You can find out more about Heap functions: heappush, heappop, heappushpop, heapify, heapreplace in heap python docs.