How can I Install a Python module within code?

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).

This should work:

import subprocess

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

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.

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])

Use:

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

I tried the above for a temporary solution instead of changing a Docker file.

Try the below. So far, it was 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)

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 requirement 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 information: Stack Overflow question: 58612272

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])}')

    import pip

try:
    import imaplib
    import email
    import pandas as pd
    # for hiding password
    from pathlib import Path
    from dotenv import load_dotenv
    import os
    import requests
    # 
    from collections import defaultdict
    from itertools import permutations,combinations
except Exception as e:
    print(e)
    e = str(e).split(' ')[-1].replace("'","")
    pip.main(['install', e])