Why are some variables and comments in my IPython notebook red?

Question

Is this a syntax highlighting issue in my iPython notebook? Can I remove it? This happens in some of my cells, but not others.

I’m viewing this iPython notebook.

Asked By: Matt

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Source

Answer 1

This is because the indentation is screwed up.
For consistency the codemirror parser will make a red line if it’s not indented 4 spaces (or if it’s indented with tabs, depending on codemirror version). The parser has some edge case that indeed highlight only a few of theses lines in red, I won’t go into details, but if you indent 4 spaces it will work.

You can either:

select the block of code and press tab
use alt–click'n'drag vertically to place multiple cursors in front of your code, and press space enough time to make the correct indent 4 space.

Setting the indent to 2 is possible, but complex and not recommended. 4 space is the python norm.

Answered By: Matt

Answer 2

This is the official solution from the Jupyter Notebook documentation:

Open a Jupyter Notebook
Select a Code Cell

Open your browser’s JavaScript console and run the following snippet:

var cell = Jupyter.notebook.get_selected_cell();
var config = cell.config;
var patch = {
      CodeCell:{
        cm_config:{indentUnit:2}
      }
    }
config.update(patch)

Reload the Notebook page

This fix is permanent.

To reverse the change repeat the process running this snippet:

var cell = Jupyter.notebook.get_selected_cell();
var config = cell.config;
var patch = {
      CodeCell:{
        cm_config:{indentUnit: null} # only change here.
      }
    }
config.update(patch)

Answered By: user4189424

Why are some variables and comments in my IPython notebook red?

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