​Regarding Atom.io editor for Python (and other languages), I'm just now discovering the Hydrogen plug-in. 

This allows highlighting contiguous lines in a script and ​treating this as a cell, as if in a Jupyter Notebook (but we're in a normal program).

The output inserts directly below.  Here's a screen shot: 

Editor split in two columns with in-line Jupyter-like output interleaved

I found this Youtube showing the user experience: 

​by Mark Jay​

As with Jupyter, you can also get LaTex symbolic output with this feature.  Still exploring.

Kirby