CODEWITHSUNDEEP
pythonpython-3.xmodulepython-module
Foxes
Foxes

Reputation: 1247

How to check if a module is installed in Python and, if not, install it within the code?

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.

Upvotes: 76

Views: 250037

Answers (12)

nonodu88
nonodu88

Reputation: 19

You can use the command pip list for determine that:

import os

try:
   pip_packages = os.popen("pip list").read()

except Exception:
        print("Error: pip is not installed")

if pip_packages.find("lib one" and "lib two") != -1:
    print("Required libs are alerty installed")

else:
     os.system("pip install lib one lib two")
     print("Required libs are installed")

Upvotes: 0

Shital Shah
Shital Shah

Reputation: 68908

For Python 3.3+ use,

import importlib
spec = importlib.util.find_spec('some_module')
if spec is not None:
    print('module is installed')

Upvotes: 6

Shawn Azdam
Shawn Azdam

Reputation: 6210

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

import importlib

packages = ['mutagen', 'gTTS']
[subprocess.check_call([sys.executable, '-m', 'pip', 'install', pkg]) 
for pkg in packages if not importlib.metadata.distribution(pkg)]

Upvotes: 3

NISHITH
NISHITH

Reputation: 21

You can do either of these things (Simple, really)

pip list | grep <package_name>

This only shows if a package is present or not The other way would be to use show ,which gives more detail:

pip show <package_name>

You can embed these in a bash script; if it doesn't return the package name, you simply pip install --user <package_name> them

Upvotes: 1

matan h
matan h

Reputation: 1162

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

Upvotes: 45

Darpan Rajput
Darpan Rajput

Reputation: 169

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

Upvotes: 4

jack
jack

Reputation: 355

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

pip list | grep <module_name_you_want_to_check>

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 <module_name_you_want_to_check>

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.

Upvotes: 33

Andrew
Andrew

Reputation: 1

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

Upvotes: 0

Girrafish
Girrafish

Reputation: 2482

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.

Upvotes: 90

dcoles
dcoles

Reputation: 4055

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'])

Upvotes: 11

Joseph Long
Joseph Long

Reputation: 278

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.

Upvotes: 1

D. Peter
D. Peter

Reputation: 517

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

Upvotes: 3

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