在 Centos 7 中并排安装 Python 版本 3 和版本 2

Question

I have a CentOS 7 machine which already has Python 2.7.5 installed. Now i want to install Python version 3 also side by side without disturbing the original Python version 2. If i install with pip i fear that it would install version 3 on top of the already existing version.

Can someone please guide me how to do the same ? Also i have created a virtualenvs directory inside my installation where i want to create the virualenvs.

At present whenever i create any virtualenvs using the virtualenv command it automatically copies the Python version 2 installable over there.

I want my virtualenvs to contain version 3 and anything outside my virtualenvs should run with version 2.

Is this even possible.

Thanks a lot for any answers.

Answer 1

For CentOS 7, we can use IUS Community repo

yum -y install https://centos7.iuscommunity.org/ius-release.rpm
yum -y install python36u
yum -y install python36u-pip
pip3.6 install numpy

So outside your virtualenv, default pip may install for python 2 not python 3.

For Python2 virtaulenv support python3, you can try:

virtualenv python2-bridge
source ./python2-bridge/bin/active
pip install --upgrade virtualenv
virtualenv -p python3 <folder>
source ./<folder>/bin/activate
python --version && pip --version
Python 3.4.3
pip 8.1.2 from /home/centos/<folder>/lib/python3.4/site-packages (python 3.4) 

Refer( https://opsech.io/posts/2016/Sep/06/creating-python-3-virtual-environments-on-centos-7.html )

Answer 2

The simplest method I know is to add the IUS Community repo for Centos 7 (only the most common x86_64 architecture is supported). Then simply install the required Python3 version directly with yum , eg yum install python36u

Link: https://ius.io/setup

Installing anything from an unknown source is a risk. The IUS has a good reputation - see eg https://wiki.centos.org/AdditionalResources/Repositories - but you must decide yourself if you want to use it.

Answer 3

In case someone stumbles upon this old thread: note that as of CentOS 7.7, python3 is included in the official repos, so you can just do

yum install python3

See https://www.liquidweb.com/kb/how-to-install-python-3-on-centos-7/

Answer 4

You can simply apt-get install python3 and then use -p python3 while creating your virtual environment. Installing python3 will not disturb your system python (2.7).