Chapter 9: Reading and writing files

Files

face Josiah Wang

You have so far opened and read some text files. Hopefully this is already natural to you by now!

Let’s spend a bit of time discussing files in a bit more detail.

What exactly are files?

A file is a named location on disk. It stores data on the hard disk.

The hard disk remembers your file even after you switch it off (it’s called non-volatile memory). Contrast this to a RAM which loses its data when you turn your computer off (volatile).

Binary vs text files

Python handles two types of files: binary and text files.

Text files are plain text files that a human can read. Your Python scripts are examples of text files. There are often \n characters at the end of each line in the file to mark a new line (these may actually be \r\n if the files were created on a Windows machine).

Most other files on your computer are binary files. For example image files like .jpg and .png, audio and video files like .mp3 or .avi, and documents like .pdf and .docx. You cannot read the content of binary files directly in the text editor (try opening an image file in a text editor and you will only see garble!) They can only be viewed in an application that ‘understands’ how to interpret the file.