Centos下更新Python到3.x

参考了知乎用户-爬上墙头大佬的文章。
Carlos Blog大佬的内容会更全面一些，但是链接似乎会被墙掉，所以把一些问题写在了这里。

安装wget

# yum install wget

下载新版本

这里用的版本是 Python3.7.0

# wget https://www.python.org/ftp/python/3.5.2/Python-3.7.0.tgz

解压缩

# tar -zxvf Python-3.7.0.tgz

创建一个空的文件夹，用来安装

说实话，这一步说我是没有走的，但是看好几篇文章都有这一步，所以我写上了

# mkdir /usr/local/python3
# yum install openssl-devel -y

编译并安装

# ./configure --prefix=/usr/local/python3
# make && make install

遇到错误

zipimport.ZipImportError: can't decompress data; zlib not available

解决方案：

是因为缺少zlib 的相关工具包导致的

# yum -y install zlib*

又遇到一个问题

Traceback (most recent call last):
  File "/home/carlos/Python-3.7.0/Lib/runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "/home/carlos/Python-3.7.0/Lib/runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "/home/carlos/Python-3.7.0/Lib/ensurepip/__main__.py", line 5, in <module>
    sys.exit(ensurepip._main())
  File "/home/carlos/Python-3.7.0/Lib/ensurepip/__init__.py", line 204, in _main
    default_pip=args.default_pip,
  File "/home/carlos/Python-3.7.0/Lib/ensurepip/__init__.py", line 117, in _bootstrap
    return _run_pip(args + [p[0] for p in _PROJECTS], additional_paths)
  File "/home/carlos/Python-3.7.0/Lib/ensurepip/__init__.py", line 27, in _run_pip
    import pip._internal
  File "/tmp/tmpgcm2i4lh/pip-10.0.1-py2.py3-none-any.whl/pip/_internal/__init__.py", line 42, in <module>
  File "/tmp/tmpgcm2i4lh/pip-10.0.1-py2.py3-none-any.whl/pip/_internal/cmdoptions.py", line 16, in <module>
  File "/tmp/tmpgcm2i4lh/pip-10.0.1-py2.py3-none-any.whl/pip/_internal/index.py", line 25, in <module>
  File "/tmp/tmpgcm2i4lh/pip-10.0.1-py2.py3-none-any.whl/pip/_internal/download.py", line 39, in <module>
  File "/tmp/tmpgcm2i4lh/pip-10.0.1-py2.py3-none-any.whl/pip/_internal/utils/glibc.py", line 3, in <module>
  File "/home/carlos/Python-3.7.0/Lib/ctypes/__init__.py", line 7, in <module>
    from _ctypes import Union, Structure, Array
ModuleNotFoundError: No module named '_ctypes'

解决方案：

3.7版本需要一个新的包libffi-devel，安装此包之后再次进行编译安装即可

# yum install libffi-devel -y

创建软链接

# ln -s /usr/local/python3/bin/python3 /usr/bin/python3
# ln -s /usr/local/python3/bin/pip3 /usr/bin/pip3

配置 yum

升级 Python 之后，由于将默认的 python 指向了 python3，yum 不能正常使用，需要编辑 yum 的配置文件：

# vi /usr/bin/yum

同时修改：

# vi /usr/libexec/urlgrabber-ext-down

将#!/usr/bin/python改为#!/usr/bin/python2.7，保存退出即可。