How to return dictionary with occurrence per word in a string (Python)?

Question

How can I make a function (given a string sentece) that returns a dictionary with each word as key and the number of occurrence as the value? (preferably without using functions like .count and .counter, basically as few shortcuts as possible.)

What I have so far doesn't seem to work and gives a key error, I have a small clue of why it doesn't work, but I'm not sure what to do to fix it. This is what I have for now:

def wordCount(sentence):
    myDict = {}
    mySentence = sentence.lower().split()

    for word in mySentence:
        if word in myDict:
           myDict[word] += 1
        else:
           myDict[word] = 1

    return myDict
wordCount("Hi hi hello")
print(myDict)

In `if word in mySentence:` probably you meant `if word in myDict:`. — jdehesa, Sep 19 '18 at 15:33
Also, if this is not a programming exercise, you can use [`collections.Counter`](https://docs.python.org/3/library/collections.html#collections.Counter) to solve this problem: `Counter(sentence.lower().split())`. — jdehesa, Sep 19 '18 at 15:34

user2390182 · Accepted Answer · 2018-09-19T16:06:27.003

1

You have been mixing up variables mySentence and myDict at one point.
You can also not use local variables outside of their scope. The following will work:

def wordCount(sentence):
    myDict = {}
    mySentence = sentence.lower().split()
    for word in mySentence:
        if word in myDict:
           myDict[word] += 1
        else:
           myDict[word] = 1
    return myDict

d = wordCount("Hi hi hello")  # assign the return value to a variable
print(d)  # so you can reuse it

edited Sep 19 '18 at 16:06

answered Sep 19 '18 at 15:33

user2390182

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Thanks, I changed that, but it still doesn't work though:/ – Charlotte Sep 19 '18 at 15:43
What exactly does not work? Do you call the function in your actual script within the function itself? I was assuming you just had the indentation wrong there. – user2390182 Sep 19 '18 at 15:44
Now i get an error saying "NameError: name 'myDict' is not defined", I call it outside the script, but still get an error – Charlotte Sep 19 '18 at 15:57
@Charlotte `myDict` is a local variable in your function. You cannot use it outside! I updated my answer. – user2390182 Sep 19 '18 at 16:02
Thanks a lot! it's solved now :) – Charlotte Sep 19 '18 at 16:06

How to return dictionary with occurrence per word in a string (Python)?

1 Answers1