Change pip path to python 3

Installing pip¶

pip is the reference Python package manager. It’s used to install and update packages. You’ll need to make sure you have the latest version of pip installed.

Unix/macOS

Debian and most other distributions include a python-pip package; if you want to use the Linux distribution-provided versions of pip, see Installing pip/setuptools/wheel with Linux Package Managers.

You can also install pip yourself to ensure you have the latest version. It’s recommended to use the system pip to bootstrap a user installation of pip:

python3 -m pip install --user --upgrade pip

python3 -m pip --version

Afterwards, you should have the latest version of pip installed in your user site:

pip 21.1.3 from $HOME/.local/lib/python3.9/site-packages (python 3.9)

Windows

The Python installers for Windows include pip. You can make sure that pip is up-to-date by running:

py -m pip install --upgrade pip

py -m pip --version

Afterwards, you should have the latest version of pip:

pip 21.1.3 from c:\python39\lib\site-packages (Python 3.9.4)

Installing virtualenv¶

Note

If you are using Python 3.3 or newer, the venv module is the preferred way to create and manage virtual environments. venv is included in the Python standard library and requires no additional installation. If you are using venv, you may skip this section.

virtualenv is used to manage Python packages for different projects. Using virtualenv allows you to avoid installing Python packages globally which could break system tools or other projects. You can install virtualenv using pip.

Unix/macOS

python3 -m pip install --user virtualenv

Windows

py -m pip install --user virtualenv

Creating a virtual environment¶

venv (for Python 3) and virtualenv (for Python 2) allow you to manage separate package installations for different projects. They essentially allow you to create a “virtual” isolated Python installation and install packages into that virtual installation. When you switch projects, you can simply create a new virtual environment and not have to worry about breaking the packages installed in the other environments. It is always recommended to use a virtual environment while developing Python applications.

To create a virtual environment, go to your project’s directory and run venv. If you are using Python 2, replace venv with virtualenv in the below commands.

The second argument is the location to create the virtual environment. Generally, you can just create this in your project and call it env.

venv will create a virtual Python installation in the env folder.

Note

You should exclude your virtual environment directory from your version control system using .gitignore or similar.

Activating a virtual environment¶

Before you can start installing or using packages in your virtual environment you’ll need to activate it. Activating a virtual environment will put the virtual environment-specific python and pip executables into your shell’s PATH.

You can confirm you’re in the virtual environment by checking the location of your Python interpreter:

It should be in the env directory:

Unix/macOS

Windows

...\env\Scripts\python.exe

As long as your virtual environment is activated pip will install packages into that specific environment and you’ll be able to import and use packages in your Python application.

Leaving the virtual environment¶

If you want to switch projects or otherwise leave your virtual environment, simply run:

If you want to re-enter the virtual environment just follow the same instructions above about activating a virtual environment. There’s no need to re-create the virtual environment.

Installing packages¶

Now that you’re in your virtual environment you can install packages. Let’s install the Requests library from the Python Package Index (PyPI):

Unix/macOS

python3 -m pip install requests

Windows

py -m pip install requests

pip should download requests and all of its dependencies and install them:

Collecting requests
  Using cached requests-2.18.4-py2.py3-none-any.whl
Collecting chardet<3.1.0,>=3.0.2 (from requests)
  Using cached chardet-3.0.4-py2.py3-none-any.whl
Collecting urllib3<1.23,>=1.21.1 (from requests)
  Using cached urllib3-1.22-py2.py3-none-any.whl
Collecting certifi>=2017.4.17 (from requests)
  Using cached certifi-2017.7.27.1-py2.py3-none-any.whl
Collecting idna<2.7,>=2.5 (from requests)
  Using cached idna-2.6-py2.py3-none-any.whl
Installing collected packages: chardet, urllib3, certifi, idna, requests
Successfully installed certifi-2017.7.27.1 chardet-3.0.4 idna-2.6 requests-2.18.4 urllib3-1.22

Installing specific versions¶

pip allows you to specify which version of a package to install using version specifiers. For example, to install a specific version of requests:

Unix/macOS

python3 -m pip install requests==2.18.4

Windows

py -m pip install requests==2.18.4

To install the latest 2.x release of requests:

Unix/macOS

python3 -m pip install requests>=2.0.0,<3.0.0

Windows

py -m pip install requests>=2.0.0,<3.0.0

To install pre-release versions of packages, use the --pre flag:

Unix/macOS

python3 -m pip install --pre requests

Windows

py -m pip install --pre requests

Installing from source¶

pip can install a package directly from source, for example:

Unix/macOS

cd google-auth
python3 -m pip install .

Windows

cd google-auth
py -m pip install .

Additionally, pip can install packages from source in development mode, meaning that changes to the source directory will immediately affect the installed package without needing to re-install:

Unix/macOS

python3 -m pip install --editable .

Windows

py -m pip install --editable .

Installing from version control systems¶

pip can install packages directly from their version control system. For example, you can install directly from a git repository:

git+https://github.com/GoogleCloudPlatform/google-auth-library-python.git#egg=google-auth

For more information on supported version control systems and syntax, see pip’s documentation on VCS Support.

Installing from local archives¶

If you have a local copy of a Distribution Package’s archive (a zip, wheel, or tar file) you can install it directly with pip:

Unix/macOS

python3 -m pip install requests-2.18.4.tar.gz

Windows

py -m pip install requests-2.18.4.tar.gz

If you have a directory containing archives of multiple packages, you can tell pip to look for packages there and not to use the Python Package Index (PyPI) at all:

Unix/macOS

python3 -m pip install --no-index --find-links=/local/dir/ requests

Windows

py -m pip install --no-index --find-links=/local/dir/ requests

This is useful if you are installing packages on a system with limited connectivity or if you want to strictly control the origin of distribution packages.

Using other package indexes¶

If you want to download packages from a different index than the Python Package Index (PyPI), you can use the --index-url flag:

Unix/macOS

python3 -m pip install --index-url http://index.example.com/simple/ SomeProject

Windows

py -m pip install --index-url http://index.example.com/simple/ SomeProject

If you want to allow packages from both the Python Package Index (PyPI) and a separate index, you can use the --extra-index-url flag instead:

Unix/macOS

python3 -m pip install --extra-index-url http://index.example.com/simple/ SomeProject

Windows

py -m pip install --extra-index-url http://index.example.com/simple/ SomeProject

Upgrading packages¶

pip can upgrade packages in-place using the --upgrade flag. For example, to install the latest version of requests and all of its dependencies:

Unix/macOS

python3 -m pip install --upgrade requests

Windows

py -m pip install --upgrade requests

Using requirements files¶

Instead of installing packages individually, pip allows you to declare all dependencies in a Requirements File. For example you could create a requirements.txt file containing:

requests==2.18.4
google-auth==1.1.0

And tell pip to install all of the packages in this file using the -r flag:

Unix/macOS

python3 -m pip install -r requirements.txt

Windows

py -m pip install -r requirements.txt

Freezing dependencies¶

Pip can export a list of all installed packages and their versions using the freeze command:

Which will output a list of package specifiers such as:

cachetools==2.0.1
certifi==2017.7.27.1
chardet==3.0.4
google-auth==1.1.1
idna==2.6
pyasn1==0.3.6
pyasn1-modules==0.1.4
requests==2.18.4
rsa==3.4.2
six==1.11.0
urllib3==1.22

This is useful for creating Requirements Files that can re-create the exact versions of all packages installed in an environment.