How to check if a Python package is installed?

In this article, we will see how to check if a python package is installed or not.

Using Exception Handling

In this method, we will use the try and exclude method. When you try, the import will be executed. If the module is imported it will automatically move forward, otherwise jump to the exception and print an error message.

try:

    import Module

    print("Already installed")

except ImportError as e:

    print("Error -> ", e)

 

output:

Error ->  No module named 'Module'

Using the importlib package

In this case, find_spec returns None if the module is not found.

Syntax: find_spec(fullname, path, target=None)

import importlib.util

 

# For illustrative purposes.

package_name = 'Module'

 

if importlib.util.find_spec(package_name) is None:

    print(package_name +" is not installed")

output:

Module is not installed

Using the OS module

Here we will execute the pip list commands and store them in a list and then check if the package is installed or not.

import os

 

stream = os.popen('pip list')

 

pip_list = stream.read()

 

Package=list(pip_list.split(" "))

# Count variable

c =

for i in Package:

    if "0.46\nopencv-python" in i:

        c = 1

 

# Checking the value of c 

if c==1:

  print("Module Installed")

else : 

  print("Module is not installed")

output:

Module is not installed