Ubuntu16.04安装Python3.6

在Ubuntu16.04上安装Python时安装不了：

执行以下命令即可安装：

#添加ppa到系统
sudo add-apt-repository ppa:jonathonf/python-3.6

此时系统会提示：

A plain backport of *just* Python 3.6. System extensions/Python libraries may or may not work.
Don't remove Python 3.5 from your system - it will break.
More info: https://launchpad.net/~jonathonf/+archive/ubuntu/python-3.6
Press [ENTER] to continue or ctrl-c to cancel adding it

按Enter即可，然后执行如下命令：

sudo apt-get update

再次安装就可以了：

sudo apt-get install python3.6

如果提示如下：

E: Failed to fetch http://ppa.launchpad.net/jonathonf/python-3.6/ubuntu/pool/main/p/python3.6/python3.6-minimal_3.6.3-1ubuntu1~16.04.york1_amd64.deb  Connection timed out
E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?

再执行一遍apt-get install就好了。