What is the primary function of read() when used on a file object?

The primary function of the read() method when used on a file object is to retrieve data from the open file. This method reads the contents of a file and returns it as a string. When you open a file in read mode, employing read() allows you to access the text or binary data stored in that file, enabling you to process or analyze that information as needed.

Using read() is essential when you want to extract data for further manipulation or display in your program. This method can read the entire contents of the file or a specified number of bytes if an argument is provided. Understanding this functionality is key in scenarios where you need to interact with data files, making it a fundamental aspect of file handling in Python.