%%cache cell magic

Defines a %%cache cell magic in the IPython notebook to cache results and outputs of long-lasting computations in a persistent pickle file. Useful when some computations in a notebook are long and you want to easily save the results in a file.

Example

• Example notebook.

Installation

• pip install ipycache

Usage

• In IPython:

  %load_ext ipycache
  

• Then, create a cell with:

  %%cache mycache.pkl var1 var2
  var1 = 1
  var2 = 2
  

• When you execute this cell the first time, the code is executed, and the variables var1 and var2 are saved in mycache.pkl in the current directory along with the outputs. Rich display outputs are only saved if you use the development version of IPython. When you execute this cell again, the code is skipped, the variables are loaded from the file and injected into the namespace, and the outputs are restored in the notebook.

• Alternatively use $file_name instead of mycache.pkl, where "file_name" is a variable holding the path to the file used for caching.

• Use the --force or -f option to force the cell's execution and overwrite the file.

• Use the --read or -r option to prevent the cell's execution and always load the variables from the cache. An exception is raised if the file does not exist.

• Use the --cachedir or -d option to specify the cache directory. You can specify a default directory in the IPython configuration file in your profile (typically in ~\.ipython\profile_default\ipython_config.py) by adding the following line:

  c.CacheMagics.cachedir = "/path/to/mycache"
  

  If both a default cache directory and the --cachedir option are given, the latter is used.