On Ubuntu 10.04 by default Python 2.6 is installed, then I have installed Python 2.7. How can I use pip install to install packages for Python 2.7.

For example:

pip install beautifulsoup4

by default installs BeautifulSoup for Python 2.6

When I do:

import bs4

in Python 2.6 it works, but in Python 2.7 it says:

No module named bs4

Use a version of pip installed against the Python instance you want to install new packages to.

In many distributions, there may be separate python2.6-pip and python2.7-pip packages, invoked with binary names such as pip-2.6 and pip-2.7. If pip is not packaged in your distribution for the desired target, you might look for a setuptools or easyinstall package, or use virtualenv (which will always include pip in a generated environment).

pip’s website includes installation instructions, if you can’t find anything within your distribution.

Alternatively, since pip itself is written in python, you can just call it with the python version you want to install the package for:

python2.7 -m pip install foo

You can execute pip module for a specific python version using the corresponding python:

Python 2.6:

python2.6 -m pip install beautifulsoup4

Python 2.7

python2.7 -m pip install beautifulsoup4

You can use this syntax

python_version -m pip install your_package

For example. If you’re running python3.5, you named it as “python3”, and want to install numpy package

python3 -m pip install numpy

In Windows, you can execute the pip module by mentioning the python version ( You need to ensure that the launcher is on your path )

py -2 -m pip install pyfora

Alternatively, if you want to install specific version of the package with the specific version of python, this is the way

sudo python2.7 -m pip install pyudev=0.16

if the “=” doesnt work, use ==

x@ubuntuserv:~$ sudo python2.7 -m pip install pyudev=0.16

Invalid requirement: ‘pyudev=0.16’ = is not a valid operator. Did you mean == ?

x@ubuntuserv:~$ sudo python2.7 -m pip install pyudev==0.16

works fine

Python 2

sudo pip2 install johnbonjovi  

Python 3

sudo pip3 install johnbonjovi

If you have both 2.7 and 3.x versions of python installed, then just rename the python exe file of python 3.x version to something like – “python.exe” to “python3.exe”. Now you can use pip for both versions individually. If you normally type “pip install ” it will consider the 2.7 version by default. If you want to install it on the 3.x version you need to call the command as “python3 -m pip install “.

For Python 3

sudo apt-get install python3-pip
sudo pip3 install beautifulsoup4

For Python 2

sudo apt-get install python2-pip
sudo pip2 install beautifulsoup4

On Debian/Ubuntu, pip is the command to use when installing packages for Python 2, while pip3 is the command to use when installing packages for Python 3.

for python2 use:

py -2 -m pip install beautifulsoup4

As with any other python script, you may specify the python installation you’d like to run it with. You may put this in your shell profile to save the alias. The $1 refers to the first argument you pass to the script.

# PYTHON3 PIP INSTALL V2
alias pip_install3="python3 -m $(which pip) install $1"

I had Python 2.7 installed via chocolatey on Windows and found pip2.7.exe in C:\tools\python2\Scripts.

Using this executable instead of the pip command installed the correct module for me (requests for Python 2.7).

I faced a similar problem with another package called Twisted. I wanted to install it for Python 2.7, but it only got installed for Python 2.6 (system’s default version).

Making a simple change worked for me.

When adding Python 2.7’s path to your $PATH variable, append it to the front like this: PATH=/usr/local/bin:$PATH, so that the system uses that version.

If you face more problems, you can follow this blog post which helped me – https://github.com/h2oai/h2o-2/wiki/installing-python-2.7-on-centos-6.3.-follow-this-sequence-exactly-for-centos-machine-only

I am installing packages from requirements.txt

pip install -r requirements.txt

The requirements.txt file reads:

Pillow
lxml
cssselect
jieba
beautifulsoup
nltk

lxml is the only package failing to install and this leads to everything failing (expected results as pointed out by larsks in the comments). However, after lxml fails pip still runs through and downloads the rest of the packages.

From what I understand the pip install -r requirements.txt command will fail if any of the packages listed in the requirements.txt fail to install.

Is there any argument I can pass when running pip install -r requirements.txt to tell it to install what it can and skip the packages that it cannot, or to exit as soon as it sees something fail?

Running each line with pip install may be a workaround.

cat requirements.txt | xargs -n 1 pip install

Note: -a parameter is not available under MacOS, so old cat is more portable.

This solution handles empty lines, whitespace lines, # comment lines, whitespace-then-# comment lines in your requirements.txt.

cat requirements.txt | sed -e '/^\s*#.*$/d' -e '/^\s*$/d' | xargs -n 1 pip install

Hat tip to this answer for the sed magic.

For Windows:

pip version >=18

import sys
from pip._internal import main as pip_main

def install(package):
    pip_main(['install', package])

if __name__ == '__main__':
    with open(sys.argv[1]) as f:
        for line in f:
            install(line)

pip version <18

import sys
import pip

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

if __name__ == '__main__':
    with open(sys.argv[1]) as f:
        for line in f:
            install(line)

The xargs solution works but can have portability issues (BSD/GNU) and/or be cumbersome if you have comments or blank lines in your requirements file.

As for the usecase where such a behavior would be required, I use for instance two separate requirement files, one which is only listing core dependencies that need to be always installed and another file with non-core dependencies that are in 90% of the cases not needed for most usecases. That would be an equivalent of the Recommends section of a debian package.

I use the following shell script (requires sed) to install optional dependencies:

#!/bin/sh

while read dependency; do
    dependency_stripped="$(echo "${dependency}" | sed -e 's/^[[:space:]]*//' -e 's/[[:space:]]*$//')"
    # Skip comments
    if [[ $dependency_stripped == \#* ]]; then
        continue
    # Skip blank lines
    elif [ -z "$dependency_stripped" ]; then
        continue
    else
        if pip install "$dependency_stripped"; then
            echo "$dependency_stripped is installed"
        else
            echo "Could not install $dependency_stripped, skipping"
        fi
    fi
done < recommends.txt

Thanks, Etienne Prothon for windows cases.

But, after upgrading to pip 18, pip package don’t expose main to public. So you may need to change code like this.

 # This code install line by line a list of pip package 
 import sys
 from pip._internal import main as pip_main

 def install(package):
    pip_main(['install', package])

 if __name__ == '__main__':
    with open(sys.argv[1]) as f:
        for line in f:
            install(line)

For Windows:

import os
from pip.__main__ import _main as main

error_log = open('error_log.txt', 'w')

def install(package):
    try:
        main(['install'] + [str(package)])
    except Exception as e:
        error_log.write(str(e))

if __name__ == '__main__':
    f = open('requirements1.txt', 'r')
    for line in f:
        install(line)
    f.close()
    error_log.close()

1. Create a local directory, and put your requirements.txt file in it.
2. Copy the code above and save it as a python file in the same directory. Remember to use .py extension, for instance, install_packages.py
3. Run this file using a cmd: python install_packages.py
4. All the packages mentioned will be installed in one go without stopping at all. :)

You can add other parameters in install function. Like: main(['install'] + [str(package)] + ['--update'])

It seems that Pipfile/Pipfile.lock are intended to be replacements for requirements.txt, in the context of Python packaging. There isn’t much documentation out there on how these actually work, however. I found an evolving description of pipfile on the PyPi section of the Python website here but it’s pretty messy and doesn’t explain the semantics of the different sections of the file.

Any pointers on how to understand these files?

The concept behind these files is simple and analogue to other already existing tools, if you have some familiarity with Ruby’s Bundler or Node’s Npm. Pipenv is both a package and virtual environment management tool that uses the Pipfile and Pipfile.lock files to achieve these goals.

Pipenv handles the virtual environment for you in one default standard way (no more activate and deactivate required). Below, some basics to get you started, see more at pipenv website.

Getting Started

Start using pipenv is easy, in your project folder type…

$ pipenv install

… and if it already has a requirements.txt file, it will generate a Pipfile file with the requirements and a virtual environment folder, otherwise, it will generate an empty Pipfile file. If you disliked or changed your mind about something that you have installed, just type…

$ pipenv uninstall <package>

… and you’re good to go. To activate the virtual environment that pipenv already generated, go with…

$ pipenv shell

… and your virtual environment will be activated. To leave the environment…

$ exit

… and you will be back to your original terminal session.

Pipfile

The Pipfile file is intended to specify packages requirements for your Python application or library, both to development and execution. You can install a package by simply using…

$ pipenv install flask

… and it will be added as a dependency for deployment and execution or by using …

$ pipenv install --dev pytest

… and it will be used as a depencency for development time. The file syntax is pretty straight forward, as follows.

[[source]] # Here goes your package sources (where you are downloading your packages from).
url = "https://pypi.python.org/simple"
verify_ssl = true
name = "pypi"

[packages] # Here goes your package requirements for running the application and its versions (which packages you will use when running the application).
requests = "*"
flask = "*"
pandas = "*"

[dev-packages] # Here goes your package requirements for developing the application and its versions (which packaes you will use when developing the application)
pylint = "*"
wheel = "*"

[requires] # Here goes your required Python version.
python_version = "3.6"

Pipfile.lock

The Pipfile.lock is intended to specify, based on the packages present in Pipfile, which specific version of those should be used, avoiding the risks of automatically upgrading packages that depend upon each other and breaking your project dependency tree.

You can lock your currently installed packages using…

$ pipenv lock

… and the tool will lookup your virtual environment folder to generate the lock file for you automatically, based on the currently installed versions. The file syntax is not as obvious as is for Pipfile , so for the sake of conciseness, it will not be displayed here.