Installing python module within code

The officially recommended way to install packages from a script is by calling pip's command-line interface via a subprocess. Most other answers presented here are not supported by pip. Furthermore since pip v10, all code has been moved to pip._internal precisely in order to make it clear to users that programmatic use of pip is not allowed.

Use sys.executable to ensure that you will call the same pip associated with the current runtime.

import subprocess
import sys

def install(package):
    subprocess.check_call([sys.executable, "-m", "pip", "install", package])

You can also use something like:

import pip

def install(package):
    if hasattr(pip, 'main'):
        pip.main(['install', package])
    else:
        pip._internal.main(['install', package])

# Example
if __name__ == '__main__':
    install('argh')

If you want to use pip to install required package and import it after installation, you can use this code:

def install_and_import(package):
    import importlib
    try:
        importlib.import_module(package)
    except ImportError:
        import pip
        pip.main(['install', package])
    finally:
        globals()[package] = importlib.import_module(package)


install_and_import('transliterate')

If you installed a package as a user you can encounter the problem that you cannot just import the package. See How to refresh sys.path? for additional information.

This should work:

import subprocess

def install(name):
    subprocess.call(['pip', 'install', name])

i added some exception handling to @Aaron's answer.

import subprocess
import sys

try:
    import pandas as pd
except ImportError:
    subprocess.check_call([sys.executable, "-m", "pip", "install", 'pandas'])
finally:
    import pandas as pd

For installing multiple packages, I am using a setup.py file with the following code:

import sys
import subprocess
import pkg_resources

required  = {'numpy', 'pandas', '<etc>'} 
installed = {pkg.key for pkg in pkg_resources.working_set}
missing   = required - installed

if missing:
    # implement pip as a subprocess:
    subprocess.check_call([sys.executable, '-m', 'pip', 'install', *missing])

You define the dependent module inside the setup.py of your own package with the "install_requires" option.

If your package needs to have some console script generated then you can use the "console_scripts" entry point in order to generate a wrapper script that will be placed within the 'bin' folder (e.g. of your virtualenv environment).

import os
os.system('pip install requests')

I tried above for temporary solution instead of changing docker file. Hope these might be useful to some

If you want a more efficient answer that expands on subprocess.check_call. You can first check if the requirement has already been met using pkg_resources.

This works for different requirment specifiers which is nice. e.g. >=, ==

import sys
import subprocess
import pkg_resources
from pkg_resources import DistributionNotFound, VersionConflict

def should_install_requirement(requirement):
    should_install = False
    try:
        pkg_resources.require(requirement)
    except (DistributionNotFound, VersionConflict):
        should_install = True
    return should_install


def install_packages(requirement_list):
    try:
        requirements = [
            requirement
            for requirement in requirement_list
            if should_install_requirement(requirement)
        ]
        if len(requirements) > 0:
            subprocess.check_call([sys.executable, "-m", "pip", "install", *requirements])
        else:
            print("Requirements already satisfied.")

    except Exception as e:
        print(e)

Example usage:

requirement_list = ['requests', 'httpx==0.18.2']
install_packages(requirement_list)

Relevant Info Stackoverflow Question: 58612272

Try the below. So far the best that worked for me Install the 4 ones first and then Mention the new ones in the REQUIRED list

import pkg_resources
import subprocess
import sys
import os

REQUIRED = {
  'spacy', 'scikit-learn', 'numpy', 'pandas', 'torch', 
  'pyfunctional', 'textblob', 'seaborn', 'matplotlib'
}

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)

To conditionally install multiple packages with exact version, I've been using this pattern basing on @Tanmay Shrivastava's answer:

import sys
from subprocess import run, PIPE, STDOUT
import pkg_resources

def run_cmd(cmd):
    ps = run(cmd, stdout=PIPE, stderr=STDOUT, shell=True, text=True)
    print(ps.stdout)


# packages to be conditionally installed with exact version
required = {"click==8.0.1", "semver==3.0.0.dev2"}
installed = {f"{pkg.key}=={pkg.version}" for pkg in pkg_resources.working_set}
missing = required - installed

if missing:
    run_cmd(f'pip install --ignore-installed {" ".join([*missing])}')