Something weird just happened to me: I mis-typed a keyboard shortcut, hitting the wrong keys, and a new notebook opened up with a Python prompt! Just for grins, I tried entering some simple Python code into the cell and evaluating it, and sure enough, it produced correct output.

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The little python-logo box to the left of the input box, if clicked, produces a drop-down menu that lets me choose Python or NodeJS.

I've done some googling, and discovered that Mathematica has a new experimental "external evaluation system". Cool! However, I have been unable to figure out what keystroke I hit that made this little gem appear. All the Mathematica docs say is that one can use the relatively clumsy ExternalEvaluate["Python",code] expression.

Does anyone know how to produce this special input cell?

  • 1
    $\begingroup$ Type > at the start of an input cell $\endgroup$
    – Carl Woll
    Commented Oct 15, 2019 at 2:15

1 Answer 1


Type > at the start of a cell (or when between cells). This is documented in an example on ref/ExternalEvaluate (last Basic Example). I'm a bit suprised it's not in the details section. It probably should be...

  • $\begingroup$ Argh. I guess I should have scrubbed through the examples more carefully… I assumed to quickly that because it is an "experimental" feature, the keyboard shortcut would be undocumented. $\endgroup$
    – ibeatty
    Commented Oct 15, 2019 at 19:50

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