Ironically, the first thing we’re going to do is show how to tell a computer to ignore a part of a program. Text written in a program but not run by the computer is called a comment. Python interprets anything after a # as a comment.

Comments can:

• Provide context for why something is written the way it is:

  # This variable will be used to count the number of times anyone tweets the word persnickety
  persnickety_count = 0

• Help other people reading the code understand it faster:

  # This code will calculate the likelihood that it will rain tomorrow
  complicated_rain_calculation_for_tomorrow()

• Ignore a line of code and see how a program will run without it:

  # useful_value = old_sloppy_code()
  useful_value = new_clean_code()