How to check version of python modules?

When you install Python, you also get the Python package manager, pip. You can use pip to get the versions of python modules and check them programmatically within your Python scripts.

Using pip freeze Command

If you want to list all installed Python modules with their version numbers, use the following command ?

$ pip freeze

You will get the output ?

asn1crypto==0.22.0
astroid==1.5.2
attrs==16.3.0
Automat==0.5.0
backports.functools-lru-cache==1.3
cffi==1.10.0
...

Finding Specific Module Version

On Linux/macOS (using grep)

To individually find the version number you can grep on this output on *NIX machines ?

$ pip freeze | grep PyMySQL

PyMySQL==0.7.11

On Windows (using findstr)

On Windows, you can use findstr instead of grep ?

PS C:\> pip freeze | findstr PyMySQL

PyMySQL==0.7.11

Checking Version Within Python Script

If you want to know the version of a module within a Python script, you can use the __version__ attribute of the module. Note that not all modules come with a __version__ attribute ?

import requests
print(requests.__version__)

2.28.1

Alternative Methods

Using pip show Command

You can get detailed information about a specific package ?

$ pip show numpy

Name: numpy
Version: 1.21.0
Summary: NumPy is the fundamental package for array computing with Python.
...

Using importlib.metadata (Python 3.8+)

For a more reliable way to check versions programmatically ?

import importlib.metadata

version = importlib.metadata.version('numpy')
print(f"NumPy version: {version}")

NumPy version: 1.21.0

Comparison

Conclusion

Use pip freeze for listing all packages, pip show for detailed package information, and importlib.metadata for reliable version checking within Python scripts. The __version__ attribute works but isn't always available.