How to find the count of a word in a string?

If you want to find the count of an individual word, just use count:

input_string.count("Hello")

Use collections.Counter and split() to tally up all the words:

from collections import Counter

words = input_string.split()
wordCount = Counter(words)

from collections import *
import re

Counter(re.findall(r"[\w']+", text.lower()))

Using re.findall is more versatile than split, because otherwise you cannot take into account contractions such as "don't" and "I'll", etc.

Demo (using your example):

>>> countWords("Hello I am going to I with hello am")
Counter({'i': 2, 'am': 2, 'hello': 2, 'to': 1, 'going': 1, 'with': 1})

If you expect to be making many of these queries, this will only do O(N) work once, rather than O(N*#queries) work.

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