Keyboard shortcut to clear cell output in Jupyter notebook

Add following at start of cell and run it:

from IPython.display import clear_output
clear_output(wait=True)

You can setup your own shortcut in the UI (for the latest master version):

This menu can be found in Help > Keyboard Shortcuts in any open notebook.

For versions less than 5:

Option 1 -- quick hack:

Change the cell type to raw then back to code: EscRY will discard the output.

Option 2 -- custom shortcut (without GUI):

For this, you need to edit the custom.js file which is typically located at ~/.jupyter/custom/custom.js (if it doesn't exist, create it).

In there, you have to add

require(['base/js/namespace']) {
    // setup 'ctrl-l' as shortcut for clearing current output
    Jupyter.keyboard_manager.command_shortcuts
           .add_shortcut('ctrl-l', 'jupyter-notebook:clear-cell-output');
}

You can add shortcut there for all the fancy things you like, since the 2nd argument can be a function (docs)

If you want mappings for other standard commands, you can dump a list of all available commands by running the following in your notebook:

from IPython.core.display import Javascript

js = """
  var jc_html = "";
  var jc_array = Object.keys(IPython.notebook.keyboard_manager.command_shortcuts.actions._actions);
  for (var i=0;i<jc_array.length;i++) {
    jc_html = jc_html + jc_array[i] + "<br >";
  }
  element.html(jc_html);
  """

Javascript(data=js, lib=None, css=None)

Just adding in for JupyterLab users. Ctrl, (advanced settings) and pasting the below in User References under keyboard shortcuts does the trick for me.

{
"shortcuts": [
        {
            "command": "notebook:hide-cell-outputs",
            "keys": [
                "H"
            ],
            "selector": ".jp-Notebook:focus"
        },
        {
            "command": "notebook:show-cell-outputs",
            "keys": [
                "Shift H"
            ],
            "selector": ".jp-Notebook:focus"
        }
    ]
}