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Python Python Collections (Retired) Dictionaries Word Count

Gary Gibson
Gary Gibson
5,011 Points
Posted by Gary Gibson
Gary Gibson
5,011 Points

I don't undertand why this code is adding anything to the empty dict.

I had to look up the correct answer to this code challenge. I get that an empty dict has been set up (a_dict = {}). I get that the count is being incremented in the for loop (for word in a_string.split()... += 1 or = 1).

What I don't get is WHY this adds anything to the empty a_dict!!!

def word_count(a_string):
    a_dict = {}
    for word in a_string.split():
        if word in a_dict:
            a_dict[word] += 1
        else:
            a_dict[word] = 1
    return a_dict
word_count.py 
# E.g. word_count("I am that I am") gets back a dictionary like:
# {'i': 2, 'am': 2, 'that': 1}
# Lowercase the string to make it easier.
# Using .split() on the sentence will give you a list of words.
# In a for loop of that list, you'll have a word that you can
# check for inclusion in the dict (with "if word in dict"-style syntax).
# Or add it to the dict with something like word_dict[word] = 1.

def word_count(a_string):
  a_dict = {}
  for word in a_string.split(" "):

2 Answers

Kourosh Raeen
Kourosh Raeen
23,733 Points
Kourosh Raeen
Kourosh Raeen
23,733 Points

The line: a_dict[word] = 1 adds a new entry to a_dict with word as the key and 1 as the value.