BUG+DOC: Recent Styler Enhancements

[attack68]

DOC: this edits the style.ipynb file to include examples of the 3 recent enhancements to Styler:

• Tooltips
• External CSS classes to datacells
• Row and Column styling via table styles

It also addresses 3 minor bugs that I detected when wirting the documentation:

BUG1 (lines 696-703): set_td_classes only attached classes to 'diagonal elements' of the DataFrame due a misaligned comprehension loop:

{
r: {
   c: [str(classes.iloc[r, c])] 
   for c, cn in enumerate(classes.columns) if not mask.iloc[r, c]
   }
for r, rn in enumerate(classes.index)
}

replaces:

{
r: {
    c: [str(classes.iloc[r, c])]
    }
for r, rn in enumerate(classes.index)
for c, cn in enumerate(classes.columns)
if not mask.iloc[r, c]
}

BUG2 (lines 513 to 537): external css class names from the set_td_classes were appended to the HTML id tag, as well as the HTML class tag, due to a premature variable update relating to the row_dict. The solution was to re-order so that 'id' tags were generated first and then 'class' was updated with information from the new methods.

BUG3 (lines 1920-1925): Tooltips were generated for the wrong indexes/columns, since the null rows/columns were dropped and then the interger locations of rows/columns was mapped. The solution was to avoid dropping null rows/columns.

[jreback]

looks good, some comments

cc @TomAugspurger

[jreback]

not sure how easy this is to link to the actual docs for these but would be great if possible.

[attack68]

i tried. i think it is possible but the relative path structure is quite complicated and i couldn't get it to work. never done it before so I have left out.

[jreback]

@attack68 can you also add tests for the bugs you have fixed (e.g. simply a check on the generated html might be fine), just to lock down these cases.

[attack68]

@jreback think this is ready now..

[jreback]

thanks @attack68

pls check the rendered docs when they build: https://pandas.pydata.org/docs/dev/