Use conda to manage different Python versions¶

Supposed you want to switch back and forth among different Python versions (python2.7, 3.4, 3.5, ...), or you want to try different environments (with or without numpy): conda is solution

install conda: http://conda.pydata.org/docs/installation.html

Note: if you have Anaconda installed, conda is already there.

To create a new enviroment with name of your_env_name, python version=3.4, preinstall numpy, scipy
```
conda create -n your_env_name python=3.4 numpy scipy
```
activate to newly created enviroment
```
source activate your_env_name
```
if you want to install new program in your_env_name, such as matplotlib
```
conda install matplotlib
```
return to your original env
```
source deactivate
```