matplotlib.axes.Axes.grouped_bar#

Axes.grouped_bar(heights,*,positions=None,group_spacing=1.5,bar_spacing=0,tick_labels=None,labels=None,orientation='vertical',colors=None,**kwargs)[source]#

Make a grouped bar plot.

Added in version 3.11:The API is still provisional. We may still fine-tune some aspects based onuser-feedback.

Grouped bar charts visualize a collection of categorical datasets. Each valuein a dataset belongs to a distinct category and these categories are the sameacross all datasets. The categories typically have string names, but couldalso be dates or index keys. The values in each dataset are represented by asequence of bars of the same color. The bars of all datasets are groupedtogether by their shared categories. The category names are drawn as the ticklabels for each bar group. Each dataset has a distinct bar color, and canoptionally get a label that is used for the legend.

Example:

grouped_bar([dataset_0,dataset_1,dataset_2],tick_labels=['A','B'],labels=['dataset 0','dataset 1','dataset 2'])

(Sourcecode,png)

Parameters:

heightslist of array-like or dict of array-like or 2D array or pandas.DataFrame

The heights for all x and groups. One of:

• list of array-like: A list of datasets, each dataset must havethe same number of elements.

  #           category_A, category_Bdataset_0 = [value_0_A, value_0_B]dataset_1 = [value_1_A, value_1_B]dataset_2 = [value_2_A, value_2_B]

  Example call:

  grouped_bar([dataset_0,dataset_1,dataset_2])

• dict of array-like: A mapping from names to datasets. Each dataset(dict value) must have the same number of elements.

  Example call:

  data_dict={'ds0':dataset_0,'ds1':dataset_1,'ds2':dataset_2}grouped_bar(data_dict)

  The names are used aslabels, i.e. this is equivalent to

  grouped_bar(data_dict.values(),labels=data_dict.keys())

  When using a dict input, you must not passlabels explicitly.

• a 2D array: The rows are the categories, the columns are the differentdatasets.

              dataset_0 dataset_1 dataset_2category_A    ds0_a     ds1_a     ds2_acategory_B    ds0_b     ds1_b     ds2_b

  Example call:

  categories=["A","B"]dataset_labels=["dataset_0","dataset_1","dataset_2"]array=np.random.random((2,3))grouped_bar(array,tick_labels=categories,labels=dataset_labels)

• apandas.DataFrame.

  The index is used for the categories, the columns are used for thedatasets.

  df=pd.DataFrame(np.random.random((2,3)),index=["A","B"],columns=["dataset_0","dataset_1","dataset_2"])grouped_bar(df)

  i.e. this is equivalent to

  grouped_bar(df.to_numpy(),tick_labels=df.index,labels=df.columns)

  Note thatgrouped_bar(df) produces a structurally equivalent plot likedf.plot.bar().

positionsarray-like, optional

The center positions of the bar groups. The values have to be equidistant.If not given, a sequence of integer positions 0, 1, 2, ... is used.

tick_labelslist of str, optional

The category labels, which are placed on ticks at the centerpositionsof the bar groups. If not set, the axis ticks (positions and labels) areleft unchanged.

labelslist of str, optional

The labels of the datasets, i.e. the bars within one group.These will show up in the legend.

group_spacingfloat, default: 1.5

The space between two bar groups as a multiple of bar width.

The default value of 1.5 thus means that there's a gap of1.5 bar widths between bar groups.

bar_spacingfloat, default: 0

The space between bars as a multiple of bar width.

orientation{"vertical", "horizontal"}, default: "vertical"

The direction of the bars.

colorslist ofcolor, optional

A sequence of colors to be cycled through and used to color barsof the different datasets. The sequence need not be exactly thesame length as the number of provided y, in which case the colorswill repeat from the beginning.

If not specified, the colors from the Axes property cycle will be used.

**kwargsRectangle properties

Properties applied to all bars. The following properties additionallyaccept a sequence of values corresponding to the datasets inheights:

• edgecolor

• facecolor

• linewidth

• linestyle

• hatch

Property	Description
agg_filter	a filter function, which takes a (m, n, 3) float array and a dpi value, and returns a (m, n, 3) array and two offsets from the bottom left corner of the image
alpha	float or None
angle	unknown
animated	bool
antialiased oraa	bool or None
bounds	(left, bottom, width, height)
capstyle	CapStyle or {'butt', 'projecting', 'round'}
clip_box	BboxBase or None
clip_on	bool
clip_path	Patch or (Path, Transform) or None
color	color
edgecolor orec	color or None
facecolor orfc	color or None
figure	Figure orSubFigure
fill	bool
gid	str
hatch	{'/', '\', '|', '-', '+', 'x', 'o', 'O', '.', '*'}
hatch_linewidth	unknown
hatchcolor	color or 'edge' or None
height	unknown
in_layout	bool
joinstyle	JoinStyle or {'miter', 'round', 'bevel'}
label	object
linestyle orls	{'-', '--', '-.', ':', '', (offset, on-off-seq), ...}
linewidth orlw	float or None
mouseover	bool
path_effects	list ofAbstractPathEffect
picker	None or bool or float or callable
rasterized	bool
sketch_params	(scale: float, length: float, randomness: float)
snap	bool or None
transform	Transform
url	str
visible	bool
width	unknown
x	unknown
xy	(float, float)
y	unknown
zorder	float

Returns:

_GroupedBarReturn

A provisional result object. This will be refined in the future.For now, the guaranteed API on the returned object is limited to

• the attributebar_containers, which is a list ofBarContainer, i.e. the results of the individualbarcalls for each dataset.

• aremove() method, that remove all bars from the Axes.See alsoArtist.remove().

See also

bar

A lower-level API for bar plots, with more degrees of freedom like individual bar sizes and colors.

Notes

For a better understanding, we compare thegrouped_bar API withthose ofbar andboxplot.

Comparison to bar()

grouped_bar intentionally deviates from thebar API in someaspects.bar(x,y) is a lower-level API and places bars with heightyat explicit positionsx. It also allows to specify individual bar widthsand colors. This kind of detailed control and flexibility is difficult tomanage and often not needed when plotting multiple datasets as a grouped barplot. Therefore,grouped_bar focusses on the abstraction of bar plotsas visualization of categorical data.

The following examples may help to transfer frombar togrouped_bar.

Positions are de-emphasized due to categories, and default to integer values.If you have usedrange(N) as positions, you can leave that value out:

bar(range(N),heights)grouped_bar([heights])

If needed, positions can be passed as keyword arguments:

bar(x,heights)grouped_bar([heights],positions=x)

To place category labels inbar you could use the argumenttick_label or use a list of category names asx.grouped_bar expects them in the argumenttick_labels:

bar(range(N),heights,tick_label=["A","B"])bar(["A","B"],heights)grouped_bar([heights],tick_labels=["A","B"])

Dataset labels, which are shown in the legend, are still passed via thelabel parameter:

bar(...,label="dataset")grouped_bar(...,label=["dataset"])

Comparison to boxplot()

Both,grouped_bar andboxplot visualize categorical datafrom multiple datasets. The basic API ontick_labels andpositionsis the same, so that you can easily switch between plotting allindividual values asgrouped_bar or the statistical distributionper category asboxplot:

grouped_bar(values,positions=...,tick_labels=...)boxplot(values,positions=...,tick_labels=...)

Examples usingmatplotlib.axes.Axes.grouped_bar#

Grouped bar chart with labels

Grouped bar chart with labels

Hat graph

Hat graph