A Concise Introduction to Programming in Python

Project: File Compression

Even though storage devices continue to become larger, file compression re-

mains an important tool for everyday computer use. For example, images are

often compressed to enable faster transmission across a network or storage on

a mobile device.

A simple compression algorithm (see, e.g., [3]) for text files is based on en-

coding long strings of repeated characters. The idea is to replace a string of

repeated characters:

!!!!!!!!

with an escape sequence made up of an otherwise rare character (such as ~),

the count, and then the repeated character:

~8!

This saves space as soon as there are at least four in a row of any character. ...