玩深度学习，经常遇到工程python版本不一致的情况，需要频繁切换版本号
一般ubuntu16.04默认的是2.7

python 3.5

sudo apt-get install python-software-properties
sudo apt-get install software-properties-common
sudo add-apt-repository ppa:fkrull/deadsnakes
sudo apt-get update
sudo apt-get install python3.5
sudo cp /usr/bin/python /usr/bin/python_bak
sudo rm /usr/bin/python
sudo ln -s /usr/bin/python3.5 /usr/bin/python
python --version

install pip3.5

wget https://bootstrap.pypa.io/get-pip.py  
sudo python3 get-pip.py  
sudo pip3 install setuptools --upgrade  
sudo pip3 install ipython[all]

install python 3.6 和对应的pip

sudo add-apt-repository ppa:jonathonf/python-3.6  # (only for 16.04 LTS)
sudo apt update
sudo apt install python3.6
sudo apt install python3.6-dev
sudo apt install python3.6-venv
wget https://bootstrap.pypa.io/get-pip.py
sudo python3.6 get-pip.py
sudo ln -s /usr/bin/python3.6 /usr/local/bin/python3
sudo ln -s /usr/local/bin/pip /usr/local/bin/pip3

When you have completed all of the above, each of the following shell commands should indicate Python 3.6.1 (or a more recent version of Python 3.6):

python --version   # (this will reflect your choice, see above)
python3 --version
$(head -1 `which pip` | tail -c +3) --version
$(head -1 `which pip3` | tail -c +3) --version

安装python3对应的tensorflow. e.g.

pip3 install -I tensorflow-gpu==1.4.1

---

错误1：
/usr/lib/python3.6/importlib/_bootstrap.py:219: RuntimeWarning: compiletime version 3.5 of module 'tensorflow.python.framework.fast_tensor_util' does not match runtime version 3.6

解决方案：
python3.6 -m pip install --upgrade --user tensorflow