Now that we’ve covered 90% of what you will write when you write a programming language, let’s look at the last 10%, reading and writing files and handling exceptional circumstances.

Time estimation: 1 hour 50 minutes

Learning objectives:

• catch an exception
• raise your own exception
• Read data from a file
• Write new data to a file
• Use with to ensure the file is closed properly.
• Use the CSV module to parse comma and tab separated datasets.