If Python is Interpreted, Why Do .pyc Files Exist?

Although Python is commonly referred to as an interpreted language, it is not strictly accurate. Interpretation is merely one level of its implementation.

From a Language Perspective

Defining Python as an interpreted language refers to its underlying language specifications, which are distinct from specific implementations. The implementation details of how Python interprets source code can vary based on the particular Python interpreter being used.

CPython Implementation

CPython, the most popular Python implementation, employs a two-step process:

• Compilation: It converts Python source code into bytecode, a lower-level representation.
• Interpretation: The bytecode is executed through a virtual machine known as the CPython Virtual Machine (CPython VM).

.pyc Files

.pyc files are the compiled bytecode versions of Python source files. They are created by CPython to optimize execution speed. When a Python program is run, CPython checks if a corresponding .pyc file exists. If it does, the .pyc file is executed instead of the source file, as this process is faster.

In summary, while Python is often considered an interpreted language due to the existence of .pyc files and the "bytecompile" process, the CPython implementation introduces an additional layer of compilation that enhances the performance of program execution.