qiskit.visualization.plot_histogram

plot_histogram(data, figsize=(7, 5), color=None, number_to_keep=None, sort='asc', target_string=None, legend=None, bar_labels=True, title=None, ax=None, filename=None)

Plot a histogram of data.

Parameters

• data (list or dict) – This is either a list of dictionaries or a single dict containing the values to represent (ex {‘001’: 130})
• figsize (tuple) – Figure size in inches.
• color (list or str) – String or list of strings for histogram bar colors.
• number_to_keep (int) – The number of terms to plot and rest is made into a single bar called ‘rest’.
• sort (string) – Could be ‘asc’, ‘desc’, ‘hamming’, ‘value’, or ‘value_desc’. If set to ‘value’ or ‘value_desc’ the x axis will be sorted by the maximum probability for each bitstring. Defaults to ‘asc’.
• target_string (str) – Target string if ‘sort’ is a distance measure.
• legend (list) – A list of strings to use for labels of the data. The number of entries must match the length of data (if data is a list or 1 if it’s a dict)
• bar_labels (bool) – Label each bar in histogram with probability value.
• title (str) – A string to use for the plot title
• ax (matplotlib.axes.Axes) – An optional Axes object to be used for the visualization output. If none is specified a new matplotlib Figure will be created and used. Additionally, if specified there will be no returned Figure since it is redundant.
• filename (str) – file path to save image to.

Returns

A figure for the rendered histogram, if the ax kwarg is not set.

Return type

matplotlib.Figure

Raises

• MissingOptionalLibraryError – Matplotlib not available.
• VisualizationError – When legend is provided and the length doesn’t match the input data.

Example

from qiskit import QuantumCircuit, BasicAer, execute
from qiskit.visualization import plot_histogram
%matplotlib inline
 
qc = QuantumCircuit(2, 2)
qc.h(0)
qc.cx(0, 1)
qc.measure([0, 1], [0, 1])
 
backend = BasicAer.get_backend('qasm_simulator')
job = execute(qc, backend)
plot_histogram(job.result().get_counts(), color='midnightblue', title="New Histogram")