Concordance
Concordance processes input text and produces a list of words, their frequencies, and itemizes which sentences they occur in.
Running
Libraries used are part of the standard Python library. This was written for the Python 2.7 interpreter.
python concordance.py
Usage
The program uses STDIN to prompt for the filename to process and prints the concordance to STDOUT. The working directory is the directory containing the Python script. Drag-and-dropping a file into the terminal will populate the entry with the absolute path to whichever file you wish to process.
Design Choice
No concordance program is perfect for the English language due to nuances. I came up with my own regex which terminates sentences after seeing a punctuation point, followed by any number of whitespaces, followed by a capital letter. It's generally ill-advised to start a sentence with a digit, so I opted to not use the regex published by others. The regex choice is appropriate for the scope of this program.
Read more on Wikipedia: https://en.wikipedia.org/wiki/Sentence_boundary_disambiguation
If a word is too large for the field size in printing, the word is truncated with an ellipsis.