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pandas.formats.style.Styler.apply
Styler.apply(func, axis=0, subset=None, **kwargs)- 
    
Apply a function column-wise, row-wise, or table-wase, updating the HTML representation with the result.
New in version 0.17.1.
Parameters: func: function
axis: int, str or None
apply to each column (
axis=0or'index') or to each row (axis=1or'columns') or to the entire DataFrame at once withaxis=None.subset: IndexSlice
a valid indexer to limit
datato before applying the function. Consider using a pandas.IndexSlicekwargs: dict
pass along to
funcReturns: self : Styler
Notes
This is similar to
DataFrame.apply, except thataxis=Noneapplies the function to the entire DataFrame at once, rather than column-wise or row-wise. 
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Licensed under the 3-clause BSD License.
 https://pandas.pydata.org/pandas-docs/version/0.18.1/generated/pandas.formats.style.Styler.apply.html