Files could be of many types, for example, text files with .txt extensions, data files in a .csv extension, or even executable files with .exe extensions. Not all file types are immediately readable. Some file types are proprietary and require specialized software to read them. An example of a proprietary file type is the PSD file that's generated by Adobe Photoshop.
We will be working with non-proprietary extensions which are easy to work with, such as .txt, .csv, and .json files for the purposes of this chapter. The skills that you will learn about will be transferrable to any other file you need to read with Python in the future.