Practice: Count Unique Words

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Write a method called count_unique_words that takes a file name and returns the number of unique tokens that appear in that file. Remember a token is a sequence of characters separated by spaces.

For example, suppose we had a file called song.txt that had the following contents.

I'm just goin' to the store, to the store
I'm just goin' to the store
You might not see me anymore, anymore
I'm just goin' to the store

If we called count_unique_words('song.txt') , it would return 14. This is because it contains the unique words ["I'm", "just", "goin'", "to", "the", "store,", "store", "You", "might", "not", "see", "me", "anymore,", "anymore"] . Notice that the tokens 'store,' and 'store' are different since they are not equal. This is intentional since we don’t want you to worry about removing punctuation.

Hint: Try to tackle this problem in parts. Start by writing the starter code like the function header and the code to go through the file word-by-word. Then think about how to store data so that you can answer how many words are unique. Is there some structure we learned that lets you store values?

Note

Some of you might be familiar with other data structures in Python called a set or dict and could help you solve this problem. We will learn about those in Lesson 5 and 6 so we don’t want you using those quite yet! Focus on using the material we have learned so far!