Mac下python2升级3

1.下载python最新版本

　链接：https://www.python.org/downloads/mac-osx/

安装默认位置为： /Library/Frameworks/Python.framework/Versions/3.x/

2.打开终端，修改~/.bash_profile文件，命令：

touch ~/.bash_profile; open ~/.bash_profile

添加代码如下：

# Setting PATH for Python 3.6
# The original version is saved in .bash_profile.pysave
PATH="/Library/Frameworks/Python.framework/Versions/3.x/bin:${PATH}"
export PATH 
alias python="/Library/Frameworks/Python.framework/Versions/3.x/bin/python3.x"

3.重启终端或执行命令：  source ~/.bash_profile