How do i know if a python module is installed or not?

I would like to install the modules 'mutagen' and 'gTTS' for my code, but I want to have it so it will install the modules on every computer that doesn't have them, but it won't try to install them if they're already installed. I currently have:

def install[package]:
    pip.main[['install', package]]

install['mutagen']

install['gTTS']

from gtts import gTTS
from mutagen.mp3 import MP3

However, if you already have the modules, this will just add unnecessary clutter to the start of the program whenever you open it.

asked May 26, 2017 at 22:00

FoxesFoxes

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4

EDIT - 2020/02/03

The pip module has updated quite a lot since the time I posted this answer. I've updated the snippet with the proper way to install a missing dependency, which is to use subprocess and pkg_resources, and not pip.

To hide the output, you can redirect the subprocess output to devnull:

import sys
import subprocess
import pkg_resources

required = {'mutagen', 'gTTS'}
installed = {pkg.key for pkg in pkg_resources.working_set}
missing = required - installed

if missing:
    python = sys.executable
    subprocess.check_call[[python, '-m', 'pip', 'install', *missing], stdout=subprocess.DEVNULL]

Like @zwer mentioned, the above works, although it is not seen as a proper way of packaging your project. To look at this in better depth, read the the page How to package a Python App.

answered May 26, 2017 at 22:07

GirrafishGirrafish

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you can use simple try/except:

try:
    import mutagen
    print["module 'mutagen' is installed"]
except ModuleNotFoundError:
    print["module 'mutagen' is not installed"]
    # or
    install["mutagen"] # the install function from the question

answered Jul 10, 2020 at 15:05

matan hmatan h

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If you want to know if a package is installed, you can check it in your terminal using the following command:

pip list | grep 

How this works:

pip list

lists all modules installed in your Python.

The vertical bar | is commonly referred to as a "pipe". It is used to pipe one command into another. That is, it directs the output from the first command into the input for the second command.

grep 

finds the keyword from the list.

Example:

pip list| grep quant

Lists all packages which start with "quant" [for example "quantstrats"]. If you do not have any output, this means the library is not installed.

karel

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answered Mar 16, 2019 at 8:29

jackjack

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You can check if a package is installed using pkg_resources.get_distribution:

import pkg_resources

for package in ['mutagen', 'gTTS']:
    try:
        dist = pkg_resources.get_distribution[package]
        print['{} [{}] is installed'.format[dist.key, dist.version]]
    except pkg_resources.DistributionNotFound:
        print['{} is NOT installed'.format[package]]

Note: You should not be directly importing the pip module as it is an unsupported use-case of the pip command.

The recommended way of using pip from your program is to execute it using subprocess:

subprocess.check_call[[sys.executable, '-m', 'pip', 'install', 'my_package']]

answered Feb 2, 2020 at 18:59

dcolesdcoles

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Although @girrafish's answer might suffice, you can check package installation via importlib too:

import importlib

packages = ['mutagen', 'gTTS']
[subprocess.check_call[['pip', 'install', pkg]] 
for pkg in packages if not importlib.util.find_spec[pkg]]

answered Nov 14, 2021 at 17:23

Shayan AmaniShayan Amani

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You can use the command line :

python -m MyModule

it will say if the module exists

Else you can simply use the best practice :

pip freeze > requirements.txt

That will put the modules you've on you python installation in a file

and :

pip install -r requirements.txt

to load them

It will automatically you purposes

Have fun

answered May 26, 2017 at 22:05

D. PeterD. Peter

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Another solution it to put an import statement for whatever you're trying to import into a try/except block, so if it works it's installed, but if not it'll throw the exception and you can run the command to install it.

answered May 26, 2017 at 22:42

Joseph LongJoseph Long

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If you would like to preview if a specific package [or some] are installed or not maybe you can use the idle in python. Specifically :

1. Open IDLE
2. Browse to File > Open Module > Some Module
3. IDLE will either display the module or will prompt an error message.

Above is tested with python 3.9.0

answered Jan 13, 2021 at 4:18

1

You can run pip show package_name or for broad view use pip list Reference

answered Jun 15, 2021 at 16:59

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