shell > yum -y install epel-release
shell > yum -y install gcc gcc-c++ wget readline-devel zlib-devel openssl-devel sqlite-devel

shell > python -V
Python 2.6.6

shell > cd /usr/local/src; wget -c https://www.python.org/ftp/python/2.7.13/Python-2.7.13.tgz
shell > tar zxf Python-2.7.13.tgz
sehll > cd Python-2.7.13
shell > ./configure && make && make install

shell > python2 -V
Python 2.7.13

shell > cd /usr/local/src; wget -c https://www.python.org/ftp/python/3.5.4/Python-3.5.4.tgz
shell > tar zxf Python-3.5.4.tgz
shell > cd Python-3.5.4
shell > ./configure && make && make install

shell > python3 -V
Python 3.5.4

shell > pip3 install virtualenv

shell > virtualenv --no-site-packages -p python2 py2.x
shell > source py2.x/bin/activate

(py2.x) shell > python -V
Python 2.7.13

(py2.x) shell > pip install ipython

(py2.x) shell > ipython
Python 2.7.13 (default, Aug 9 2017, 20:15:06) 
Type "copyright", "credits" or "license" for more information.

IPython 5.4.1 -- An enhanced Interactive Python.
? -> Introduction and overview of IPython‘s features.
%quickref -> Quick reference.
help -> Python‘s own help system.
object? -> Details about ‘object‘, use ‘object??‘ for extra details.

In [1]:

(py2.x) shell > deactivate

# 创建了一个 python2 的虚拟环境 名称为 py2.x，之后激活这个虚拟环境
# 可以看到默认的 python 版本已经不是原来的 2.6.6
# 使用 pip 安装 ipython 软件包
# ipython 调用的 python 版本也是 2.7.13
# 退出虚拟环境

shell > virtualenv --no-site-packages -p python3 py3.x
shell > source py3.x/bin/activate

(py3.x) shell > python -V
Python 3.5.4

(py3.x) shell > pip install ipython

(py3.x) shell > ipython
Python 3.5.4 (default, Aug 9 2017, 21:57:01) 
Type ‘copyright‘, ‘credits‘ or ‘license‘ for more information
IPython 6.1.0 -- An enhanced Interactive Python. Type ‘?‘ for help.

In [1]:

(py3.x) shell > deactivate