How can I follow the cell currently being run in a Jupyter notebook?

Question

After I select run all, run all above, or run all below in a Jupyter notebook, how can I follow the cell currently being run in a Jupyter notebook? I.e., I want the cell that is displayed to me to be the one being run, throughout the execution of the notebook.

Answer 1

Add the following in ~/.jupyter/custom/custom.js and reload the notebooks you're running:

/*
 In Command mode Meta-[ toggles Follow Exec Cell mode, Meta-] turns it off.

 To adjust the behavior you can adjust the arguments:
 * behavior: One of "auto", "instant", or "smooth". Defaults to "auto". Defines the transition animation.
 * block:    One of "start", "center", "end", or "nearest". Defaults to "center".
 * inline:   One of "start", "center", "end", or "nearest". Defaults to "nearest".
 https://developer.mozilla.org/en-US/docs/Web/API/Element/scrollIntoView
*/
function scrollIntoRunningCell(evt, data) {
    $('.running')[0].scrollIntoView({behavior: 'smooth', inline: 'center'});
}

Jupyter.keyboard_manager.command_shortcuts.add_shortcut('Meta-[', {
    help: 'Follow Executing Cell On',
    help_index: 'zz',
    handler: function (event) {
        Jupyter.notebook.events.on('finished_execute.CodeCell', scrollIntoRunningCell);
        //console.log("Follow Executing Cell On")
        return false;
    }
});

Jupyter.keyboard_manager.command_shortcuts.add_shortcut('Meta-]', {
    help: 'Follow Executing Cell Off',
    help_index: 'zz',
    handler: function (event) {
        Jupyter.notebook.events.off('finished_execute.CodeCell', scrollIntoRunningCell);
        //console.log("Follow Executing Cell Off")
        return false;
    }
});

Now in Command Mode (when cell in focus has a blue box around it and not green, or hit Esc to toggle mode), hit Meta-[ to get the currently run cell stay in the middle of the screen, hit Meta-] to return to normal behavior.

If this is not working, debug this setup by uncommenting console.log() calls and watch your browser Developer Tools' Console to check that custom.js got loaded without errors and that the shortcuts got registered and the handler is activated. Sometimes you need to restart jupyter notebook, but most of the time tab-reload works.

If you just want to jump once to the current executing cell use Alt-I after you add the following to ~/.jupyter/custom/custom.js and reload the notebooks you're running:

// Alt-I: Go to Running cell shortcut [Command mode]
Jupyter.keyboard_manager.command_shortcuts.add_shortcut('Alt-I', {
    help : 'Go to Running cell',
    help_index : 'zz',
    handler : function (event) {
        setTimeout(function() {
            // Find running cell and click the first one
            if ($('.running').length > 0) {
                //alert("found running cell");
                $('.running')[0].scrollIntoView();
            }}, 250);
        return false;
    }
});

Caveat: for it to work - the sections should all be uncollapsed - otherwise it won't know to go into a collapsed section.

You can adjust the activation shortcut keys to your liking.

Remember that all 3 shortcuts will only work in the Command mode (see above for figuring that out).

This has been tested to work with jupyter notebook 5.6.0 with python 3.6.6.