Difference between pickle and opening a file?

Question

What is the difference between using the pickle library and using with open()?

Both have the same functionality where you read and write into the file and I don't see any differences between them.

And why do many people use pickle more than with open() if it is so seemingly similar?

Answer 1

Let me see if I can understand where the point of confusion is and give a useful explanation.

open is how you get a file object, which is the interface between your Python program and an actual file on disk. with is a tool used for ensuring that the file object is closed at the appropriate time.

The file object allows you to read and/or write the file, depending on how it was opened. The built-in way to do this is with the object's own functionality. This lets you write whatever data you want, at the expense that you are responsible for figuring out what that data should be; alternately, it lets you read the data and gives you both the power and responsibility that comes from interpreting that data.

The pickle library builds on top of that functionality, to use the file's contents to represent native Python objects. It does the interpretation (parsing) and data-figuring-out (formatting) work for you, accomplishing something that would be difficult by hand. The trade-off is that it works in a specific way, and is fit for only a specific purpose - you won't, for example, be producing or interpreting plain text files, or images, or JSON data, etc. this way any time soon (which you could by writing the data yourself, or by using a different, special-purpose library - except of course for plain text, where there's no point in doing anything beyond using the built-in functionality).