How to split and merge cells in JupyterLab

In JupyterLab, given the following code cell, how may it be split into multiple cells?

Likewise, given the following cells, how may they be combined into a single cell?

Solution

When working directly with JupyterLab, not in an IDE.

JupyterLab: splitCell
- Source
In order to split one cell into many cells:
- Place cursors where the split is desired, and then press and release ctrl + shift + -
- Multiple cursors may be placed, by holding ctrl, and clicking the location for the cursor.

JupyterLab: mergeCells
- Source
In order to merge multiple cells, into one cell:
- Select the desired, consecutive cells, by holding shift, and clicking in the margin, where the [ ] is, which will highlight the selected cells.
- While still holding shift, press m, and then release both keys.

The resulting merged cell, will have a space between the code from each cell, as does the first image in this answer.
- This is the expected behavior newModel.value.text = toMerge.join('\n\n');

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