def bar(self, x=None, y=None, **kwds):
return self(kind='<STR_LIT:bar>', x=x, y=y, **kwds)<EOL>
Vertical bar plot.

A bar plot is a plot that presents categorical data with
rectangular bars with lengths proportional to the values that they
represent. A bar plot shows comparisons among discrete categories. One
axis of the plot shows the specific categories being compared, and the
other axis represents a measured value.

Parameters
----------
x : label or position, optional
    Allows plotting of one column versus another. If not specified,
    the index of the DataFrame is used.
y : label or position, optional
    Allows plotting of one column versus another. If not specified,
    all numerical columns are used.
**kwds
    Additional keyword arguments are documented in
    :meth:`DataFrame.plot`.

Returns
-------
matplotlib.axes.Axes or np.ndarray of them
    An ndarray is returned with one :class:`matplotlib.axes.Axes`
    per column when ``subplots=True``.

See Also
--------
DataFrame.plot.barh : Horizontal bar plot.
DataFrame.plot : Make plots of a DataFrame.
matplotlib.pyplot.bar : Make a bar plot with matplotlib.

Examples
--------
Basic plot.

.. plot::
    :context: close-figs

    >>> df = pd.DataFrame({'lab':['A', 'B', 'C'], 'val':[10, 30, 20]})
    >>> ax = df.plot.bar(x='lab', y='val', rot=0)

Plot a whole dataframe to a bar plot. Each column is assigned a
distinct color, and each row is nested in a group along the
horizontal axis.

.. plot::
    :context: close-figs

    >>> speed = [0.1, 17.5, 40, 48, 52, 69, 88]
    >>> lifespan = [2, 8, 70, 1.5, 25, 12, 28]
    >>> index = ['snail', 'pig', 'elephant',
    ...          'rabbit', 'giraffe', 'coyote', 'horse']
    >>> df = pd.DataFrame({'speed': speed,
    ...                    'lifespan': lifespan}, index=index)
    >>> ax = df.plot.bar(rot=0)

Instead of nesting, the figure can be split by column with
``subplots=True``. In this case, a :class:`numpy.ndarray` of
:class:`matplotlib.axes.Axes` are returned.

.. plot::
    :context: close-figs

    >>> axes = df.plot.bar(rot=0, subplots=True)
    >>> axes[1].legend(loc=2)  # doctest: +SKIP

Plot a single column.

.. plot::
    :context: close-figs

    >>> ax = df.plot.bar(y='speed', rot=0)

Plot only selected categories for the DataFrame.

.. plot::
    :context: close-figs

    >>> ax = df.plot.bar(x='lifespan', rot=0)