In this challenge we would like you to find the most used word in a book. The word should not be part of the common English words (i.e. the, a, I, is).


Copyright free books for use are available via Project Guttenburg. We suggest the book titled “The Importance of Being Earnest” by Oscar Wilde.

A comma separated list of all the common English words is available at:

Suggested approach

A suggested algorithm to find the most common word is:

  • Pull the content of the book into a collection
  • Use a regular expression to create a collection of individual words - eg. #”[a-zA-Z0-9 ’]+”
  • Convert all the words to lower case so they match with common words source
  • Remove the common English words used in the book
  • Count the occurrences of the remaining words (eg. each word is associated with the number of times it appears in the book)
  • Sort the words by the number of the occurrences
  • Reverse the collection so the most commonly used word is shown first

(str "Delete me and add your code to solve the challenge.  Use a Clojure editor if you prefer")

Once you have solved this challenge, take a look at the suggested answers to the problem.