centos7安装python3，并配置虚拟环境（超级详细教程）

安装python3

    1. centos7自带python2环境

[root@iZuf62qojdpdfmeohedn2jZ ~]# python -V
Python 2.7.5
[root@iZuf62qojdpdfmeohedn2jZ ~]# pip -V
pip 19.1.1 from /usr/lib/python2.7/site-packages/pip (python 2.7)

    2. 安装可能用到的依赖

yum install openssl-devel bzip2-devel expat-devel gdbm-devel readline-devel sqlite-devel

    3. 利用wget命令下载python3.6.5，没有wget命令的话，需要先下载

[root@iZuf62qojdpdfmeohedn2jZ ~]# yum install -y wget

    接下来下载python3.6.5

[root@iZuf62qojdpdfmeohedn2jZ ~]# wget https://www.python.org/ftp/python/3.6.5/Python-3.6.5.tgz

    4. 下载的是一个压缩包，解压

[root@iZuf62qojdpdfmeohedn2jZ ~]# tar -zxvf Python-3.6.5.tgz

    5. 进入该目录，进行编译，指定编译后生成文件的位置

[root@iZuf62qojdpdfmeohedn2jZ ~]# cd Python-3.6.5/
[root@iZuf62qojdpdfmeohedn2jZ Python-3.6.5]# ./configure --prefix=/usr/local/python3

  如果遇到：configure: error: no acceptable C compiler found in $PATH

yum install gcc

    6. 接下来开始安装

    由于之前踩过坑，在安装的过程中可能报错，大致意思就是：缺少了zlib的解压缩类库。所以我们先下载zlib解压缩类库

[root@iZuf62qojdpdfmeohedn2jZ Python-3.6.5]# yum install -y zlib*

    然后再开始安装

[root@iZuf62qojdpdfmeohedn2jZ Python-3.6.5]# make && make install

    出现以下提示说明安装成功：

if test "x" != "x" ; then \
	rm -f /usr/local/python3/bin/python3-32; \
	(cd /usr/local/python3/bin; ln -s python3.6-32 python3-32) \
fi
rm -f /usr/local/python3/share/man/man1/python3.1
(cd /usr/local/python3/share/man/man1; ln -s python3.6.1 python3.1)
if test "xupgrade" != "xno"  ; then \
	case upgrade in \
		upgrade) ensurepip="--upgrade" ;; \
		install|*) ensurepip="" ;; \
	esac; \
	 ./python -E -m ensurepip \
		$ensurepip --root=/ ; \
fi
Collecting setuptools
Collecting pip
Installing collected packages: setuptools, pip
Successfully installed pip-9.0.3 setuptools-39.0.1
[root@iZuf62qojdpdfmeohedn2jZ Python-3.6.5]# 

    7. 设置软连接

[root@iZuf62qojdpdfmeohedn2jZ /]# ln -s /usr/local/python3/bin/python3 /usr/bin/python3
[root@iZuf62qojdpdfmeohedn2jZ /]# ln -s /usr/local/python3/bin/pip3 /usr/bin/pip3

    8. 测试

[root@iZuf62qojdpdfmeohedn2jZ /]# python3 -V
Python 3.6.5
[root@iZuf62qojdpdfmeohedn2jZ /]# pip3 -V
pip 9.0.3 from /usr/local/python3/lib/python3.6/site-packages (python 3.6)
[root@iZuf62qojdpdfmeohedn2jZ /]# python3
Python 3.6.5 (default, Nov 13 2020, 10:51:33) 
[GCC 4.8.5 20150623 (Red Hat 4.8.5-36)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> 
[root@iZuf62qojdpdfmeohedn2jZ /]# 

    9. 至此，安装成功！！

==============================分割线==============================

配置虚拟环境

    1. 先新建一个文件夹，用来作为虚拟环境的目录

[root@iZuf62qojdpdfmeohedn2jZ /]# mkdir envs
[root@iZuf62qojdpdfmeohedn2jZ /]# ls
bin   dev   etc   lib    lost+found  mnt  proc  run   srv  tmp  var
boot  envs  home  lib64  media       opt  root  sbin  sys  usr
[root@iZuf62qojdpdfmeohedn2jZ /]#

    2.下载virtualanv和virtualenvwrapper

[root@iZuf62qojdpdfmeohedn2jZ /]# pip3 install virtualenv
[root@iZuf62qojdpdfmeohedn2jZ /]# pip3 install virtualenvwrapper

    3. 配置环境变量

[root@iZuf62qojdpdfmeohedn2jZ /]# find / -name 'virtualenvwrapper.sh'
/usr/local/python3/bin/virtualenvwrapper.sh
[root@iZuf62qojdpdfmeohedn2jZ /]# vim usr/local/python3/bin/virtualenvwrapper.sh 

    现修改python为python3

if [ "${VIRTUALENVWRAPPER_PYTHON:-}" = "" ]
then
    # 修改之前的
    # VIRTUALENVWRAPPER_PYTHON="$(command \which python)"
    # 修改之后的，python后边加个3
    VIRTUALENVWRAPPER_PYTHON="$(command \which python3)"
fi

    打开bashrc文件：

[root@iZuf62qojdpdfmeohedn2jZ /]# vim ~/.bashrc

    并在末尾添加以下几行：

export WORKON_HOME=/envs
export VIRTUELANVWRAPPER_PYTHON=/usr/bin/python3
source /usr/local/python3/bin/virtualenvwrapper.sh

    执行：source ~/.bashrc

[root@iZuf62qojdpdfmeohedn2jZ /]# source ~/.bashrc 
virtualenvwrapper.user_scripts creating /envs/premkproject
virtualenvwrapper.user_scripts creating /envs/postmkproject
virtualenvwrapper.user_scripts creating /envs/initialize
virtualenvwrapper.user_scripts creating /envs/premkvirtualenv
virtualenvwrapper.user_scripts creating /envs/postmkvirtualenv
virtualenvwrapper.user_scripts creating /envs/prermvirtualenv
virtualenvwrapper.user_scripts creating /envs/postrmvirtualenv
virtualenvwrapper.user_scripts creating /envs/predeactivate
virtualenvwrapper.user_scripts creating /envs/postdeactivate
virtualenvwrapper.user_scripts creating /envs/preactivate
virtualenvwrapper.user_scripts creating /envs/postactivate
virtualenvwrapper.user_scripts creating /envs/get_env_details
[root@iZuf62qojdpdfmeohedn2jZ /]#

    4. 解决报错

    此时输入workon，什么都不输出，说明没有创建虚拟环境

[root@iZuf62qojdpdfmeohedn2jZ /]# workon
[root@iZuf62qojdpdfmeohedn2jZ /]

    创建虚拟环境，报错如下：

[root@iZuf62qojdpdfmeohedn2jZ /]# mkvirtualenv py3scrapy
which: no virtualenv in (/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin)
ERROR: virtualenvwrapper could not find virtualenv in your path
[root@iZuf62qojdpdfmeohedn2jZ /]# mkvirtualenv -p python3 py3scrapy
which: no virtualenv in (/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin)
ERROR: virtualenvwrapper could not find virtualenv in your path
[root@iZuf62qojdpdfmeohedn2jZ /]

    解决办法：

[root@iZuf62qojdpdfmeohedn2jZ /]# cd /usr/bin/
[root@iZuf62qojdpdfmeohedn2jZ bin]# ls -al |grep virtualenv
[root@iZuf62qojdpdfmeohedn2jZ bin]# cd /usr/local/python3/bin/
[root@iZuf62qojdpdfmeohedn2jZ bin]# ln virtualenv /usr/bin/virtualenv

    5. 创建虚拟环境

[root@iZuf62qojdpdfmeohedn2jZ /]# mkvirtualenv test
created virtual environment CPython3.6.5.final.0-64 in 191ms
  creator CPython3Posix(dest=/envs/test, clear=False, global=False)
  seeder FromAppData(download=False, pip=bundle, setuptools=bundle, wheel=bundle, via=copy, app_data_dir=/root/.local/share/virtualenv)
    added seed packages: pip==20.2.4, setuptools==50.3.2, wheel==0.35.1
  activators BashActivator,CShellActivator,FishActivator,PowerShellActivator,PythonActivator,XonshActivator
virtualenvwrapper.user_scripts creating /envs/test/bin/predeactivate
virtualenvwrapper.user_scripts creating /envs/test/bin/postdeactivate
virtualenvwrapper.user_scripts creating /envs/test/bin/preactivate
virtualenvwrapper.user_scripts creating /envs/test/bin/postactivate
virtualenvwrapper.user_scripts creating /envs/test/bin/get_env_details
(test) [root@iZuf62qojdpdfmeohedn2jZ /]# wrokon
-bash: wrokon: command not found
(test) [root@iZuf62qojdpdfmeohedn2jZ /]# workon
py3scrapy
test
(test) [root@iZuf62qojdpdfmeohedn2jZ /]# 

    6. 退出、删除、列出虚拟环境

(test) [root@iZuf62qojdpdfmeohedn2jZ /]# deactivate
[root@iZuf62qojdpdfmeohedn2jZ /]# rmvirtualenv test
Removing test...
[root@iZuf62qojdpdfmeohedn2jZ /]# workon
py3scrapy
[root@iZuf62qojdpdfmeohedn2jZ /]# 

    7. 大功告成！！！