pandas.io.formats.style.Styler.apply

Styler.apply(func, axis=0, subset=None, **kwargs)[source]

Apply a CSS-styling function column-wise, row-wise, or table-wise.

Updates the HTML representation with the result.

Parameters

func:function

func should take a Series if axis in [0,1] and return an object of same length, also with identical index if the object is a Series. func should take a DataFrame if axis is None and return either an ndarray with the same shape or a DataFrame with identical columns and index.

Changed in version 1.3.0.

axis:{0 or ‘index’, 1 or ‘columns’, None}, default 0

Apply to each column (axis=0 or 'index'), to each row (axis=1 or 'columns'), or to the entire DataFrame at once with axis=None.

subset:label, array-like, IndexSlice, optional

A valid 2d input to DataFrame.loc[<subset>], or, in the case of a 1d input or single key, to DataFrame.loc[:, <subset>] where the columns are prioritised, to limit data to before applying the function.

**kwargs:dict

Pass along to func.

Returns

self:Styler

See also

Styler.applymap

Apply a CSS-styling function elementwise.

Notes

The elements of the output of func should be CSS styles as strings, in the format ‘attribute: value; attribute2: value2; …’ or, if nothing is to be applied to that element, an empty string or None.

This is similar to DataFrame.apply, except that axis=None applies the function to the entire DataFrame at once, rather than column-wise or row-wise.

Examples

>>> def highlight_max(x, color):
...     return np.where(x == np.nanmax(x.to_numpy()), f"color: {color};", None)
>>> df = pd.DataFrame(np.random.randn(5, 2), columns=["A", "B"])
>>> df.style.apply(highlight_max, color='red')
>>> df.style.apply(highlight_max, color='blue', axis=1)
>>> df.style.apply(highlight_max, color='green', axis=None)

Using subset to restrict application to a single column or multiple columns

>>> df.style.apply(highlight_max, color='red', subset="A")
>>> df.style.apply(highlight_max, color='red', subset=["A", "B"])

Using a 2d input to subset to select rows in addition to columns

>>> df.style.apply(highlight_max, color='red', subset=([0,1,2], slice(None))
>>> df.style.apply(highlight_max, color='red', subset=(slice(0,5,2), "A")