问题
I'm currently working with pandas and ipython. Since pandas dataframes are copied when you perform operations with it, my memory usage increases by 500 mb with every cell. I believe it's because the data gets stored in the Out variable, since this doesn't happen with the default python interpreter.
How do I disable the Out variable?
回答1:
The first option you have is to avoid producing output. If you don't really need to see the intermediate results just avoid them and put all the computations in a single cell.
If you need to actually display that data you can use InteractiveShell.cache_size option to set a maximum size for the cache. Setting this value to 0 disables caching.
To do so you have to create a file called ipython_config.py (or ipython_notebook_config.py) under your ~/.ipython/profile_default directory with the contents:
c = get_config()
c.InteractiveShell.cache_size = 0
After that you'll see:
In [1]: 1
Out[1]: 1
In [2]: Out[1]
---------------------------------------------------------------------------
KeyError Traceback (most recent call last)
<ipython-input-2-d74cffe9cfe3> in <module>()
----> 1 Out[1]
KeyError: 1
You can also create different profiles for ipython using the command ipython profile create <name>. This will create a new profile under ~/.ipython/profile_<name> with a default configuration file. You can then launch ipython using the --profile <name> option to load that profile.
Alternatively you can use the %reset out magic to reset the output cache or use the %xdel magic to delete a specific object:
In [1]: 1
Out[1]: 1
In [2]: 2
Out[2]: 2
In [3]: %reset out
Once deleted, variables cannot be recovered. Proceed (y/[n])? y
Flushing output cache (2 entries)
In [4]: Out[1]
---------------------------------------------------------------------------
KeyError Traceback (most recent call last)
<ipython-input-4-d74cffe9cfe3> in <module>()
----> 1 Out[1]
KeyError: 1
In [5]: 1
Out[5]: 1
In [6]: 2
Out[6]: 2
In [7]: v = Out[5]
In [8]: %xdel v # requires a variable name, so you cannot write %xdel Out[5]
In [9]: Out[5] # xdel removes the value of v from Out and other caches
---------------------------------------------------------------------------
KeyError Traceback (most recent call last)
<ipython-input-9-573c4eba9654> in <module>()
----> 1 Out[5]
KeyError: 5
来源：https://stackoverflow.com/questions/37808904/prevent-ipython-from-storing-outputs-in-out-variable