在准備安裝python3和pip3時，請先安裝依賴環境：yum install -y libffi-devel，和 yum -y install zlib-devel bzip2-devel openssl-devel ncurses-devel sqlite-devel readline-devel tk-devel gdbm-devel db4-devel libpcap-devel xz-devel一定要先裝！不然會出現如下例一連串連鎖反應的bug
在安裝linux的centos里安裝python3報錯：
File "/usr/local/src/Python-3.7.0/Lib/ctypes/__init__.py", line 7, in <module>
from _ctypes import Union, Structure, Array
ModuleNotFoundError: No module named ‘_ctypes‘
make: *** [install] Error 1
踩坑踩得我不要不要的，此處報錯，是沒有安裝依賴環境yum install -y libffi-devel導致，若此處報錯，你的stuptools,pip 都安裝不上，正確姿勢應該是這樣
Looking in links: /tmp/tmplw5bl0fh
Collecting setuptools
Collecting pip
Installing collected packages: setuptools, pip
Successfully installed pip-19.0.3 setuptools-40.8.0
pip需要用的環境:yum -y install zlib-devel bzip2-devel openssl-devel ncurses-devel sqlite-devel readline-devel tk-devel gdbm-devel db4-devel libpcap-devel xz-devel，不安裝軟連接無法添加，即便添加了也是2.7的版本
另外當你在安裝python3時報上面的錯，你再去安裝yum install -y libffi-devel，會報找不到python這個文件夾，因為你用mv python python.bak 命令備份並且將其刪除了，所以，你需要先將python恢復。
這里附上恢復python作者文章地址 https://www.cnblogs.com/sueyyyy/p/10410832.html
安裝python3和pip3的作者地址：https://www.cnblogs.com/yoyoketang/p/10195102.html
繼續踩坑去，感覺后面無數的坑等着我。。。。在心里為自己點無數根蠟，wish yourself luck
