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Here we go with processing files.

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Up until now, the only data that our programs have processed,

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the only inputs have either come from literals that we put into

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the program itself or things that the user typed during execution,

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as a result of a call to the input function.

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The only place where outputs have gone is the output window,

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which doesn't persist after you go to another page in the textbook.

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A file contains data that persists between execution of your program.

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As a computer user,

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you're already familiar with the concept of files,

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you've probably worked with image files and spreadsheet files and word processing files.

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In this lesson, you'll learn how to manipulate files in a Python program.

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We'll only be working with text files,

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not audio or other binary formats.

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At the end of this lesson,

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you should be able to write a program that reads a file's contents,

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either as a single string or line by line,

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you should be able to use relative paths to specify the location of a file,

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you should be able to write new text to a file.

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I'll see you at the end for a wrap-up and more geeky humor.