Check if module exists, if not install it

Question

I want to check if a module exists, if it doesn\'t I want to install it.

How should I do this?

So far I have this code which correctly prints f

Answer 1

Here is how it should be done, and if I am wrong, please correct me. However, Noufal seems to confirm it in another answer to this question, so I guess it's right.

When writing the setup.py script for some scripts I wrote, I was dependent on the package manager of my distribution to install the required library for me.

So, in my setup.py file, I did this:

package = 'package_name'
try:
    return __import__(package)
except ImportError:
    return None

So if package_name was installed, fine, continue. Else, install it via the package manager which I called using subprocess.

Answer 2

NOTE: Ipython / Jupyter specific solution.

While using notebooks / online kernels, I usually do it using systems call.

try:
  import keyring
except:
  !pip install pulp
  import keyring

Answer 3

You can launch pip install %s"%keyring in the except part to do this but I don't recommend it. The correct way is to package your application using distutils so that when it's installed, dependencies will be pulled in.

Answer 4

Not all modules can be installed so easily. Not all of them have easy-install support, some can only be installed by building them.. others require some non-python prerequisites, like gcc, which makes things even more complicated (and forget about it working well on Windows).

So I would say you could probably make it work for some predetermined modules, but there's no chance it'll be something generic that works for any module.

Answer 5

import pip

def import_or_install(package):
    try:
        __import__(package)
    except ImportError:
        pip.main(['install', package])       

This code simply attempt to import a package, where package is of type str, and if it is unable to, calls pip and attempt to install it from there.

Answer 6

I made an import_neccessary_modules() function to fix this common issue.

# ======================================================================================
# == Fix any missing Module, that need to be installed with PIP.exe. [Windows System] ==
# ======================================================================================
import importlib, os
def import_neccessary_modules(modname:str)->None:
    '''
        Import a Module,
        and if that fails, try to use the Command Window PIP.exe to install it,
        if that fails, because PIP in not in the Path,
        try find the location of PIP.exe and again attempt to install from the Command Window.
    '''
    try:
        # If Module it is already installed, try to Import it
        importlib.import_module(modname)
        print(f"Importing {modname}")
    except ImportError:
        # Error if Module is not installed Yet,  the '\033[93m' is just code to print in certain colors
        print(f"\033[93mSince you don't have the Python Module [{modname}] installed!")
        print("I will need to install it using Python's PIP.exe command.\033[0m")
        if os.system('PIP --version') == 0:
            # No error from running PIP in the Command Window, therefor PIP.exe is in the %PATH%
            os.system(f'PIP install {modname}')
        else:
            # Error, PIP.exe is NOT in the Path!! So I'll try to find it.
            pip_location_attempt_1 = sys.executable.replace("python.exe", "") + "pip.exe"
            pip_location_attempt_2 = sys.executable.replace("python.exe", "") + "scripts\pip.exe"
            if os.path.exists(pip_location_attempt_1):
                # The Attempt #1 File exists!!!
                os.system(pip_location_attempt_1 + " install " + modname)
            elif os.path.exists(pip_location_attempt_2):
                # The Attempt #2 File exists!!!
                os.system(pip_location_attempt_2 + " install " + modname)
            else:
                # Neither Attempts found the PIP.exe file, So i Fail...
                print(f"\033[91mAbort!!!  I can't find PIP.exe program!")
                print(f"You'll need to manually install the Module: {modname} in order for this program to work.")
                print(f"Find the PIP.exe file on your computer and in the CMD Command window...")
                print(f"   in that directory, type    PIP.exe install {modname}\033[0m")
                exit()


import_neccessary_modules('art')
import_neccessary_modules('pyperclip')
import_neccessary_modules('winsound')