.. _sphx_glr_gallery_statistics_errorbars_and_boxes.py: ==================================================== Creating boxes from error bars using PatchCollection ==================================================== In this example, we snazz up a pretty standard error bar plot by adding a rectangle patch defined by the limits of the bars in both the x- and y- directions. To do this, we have to write our own custom function called ``make_error_boxes``. Close inspection of this function will reveal the preferred pattern in writing functions for matplotlib: 1. an ``Axes`` object is passed directly to the function 2. the function operates on the `Axes` methods directly, not through the ``pyplot`` interface 3. plotting kwargs that could be abbreviated are spelled out for better code readability in the future (for example we use ``facecolor`` instead of ``fc``) 4. the artists returned by the ``Axes`` plotting methods are then returned by the function so that, if desired, their styles can be modified later outside of the function (they are not modified in this example). .. image:: /gallery/statistics/images/sphx_glr_errorbars_and_boxes_001.png :align: center .. code-block:: python import numpy as np import matplotlib.pyplot as plt from matplotlib.collections import PatchCollection from matplotlib.patches import Rectangle # Number of data points n = 5 # Dummy data np.random.seed(19680801) x = np.arange(0, n, 1) y = np.random.rand(n) * 5. # Dummy errors (above and below) xerr = np.random.rand(2, n) + 0.1 yerr = np.random.rand(2, n) + 0.2 def make_error_boxes(ax, xdata, ydata, xerror, yerror, facecolor='r', edgecolor='None', alpha=0.5): # Create list for all the error patches errorboxes = [] # Loop over data points; create box from errors at each point for x, y, xe, ye in zip(xdata, ydata, xerror.T, yerror.T): rect = Rectangle((x - xe[0], y - ye[0]), xe.sum(), ye.sum()) errorboxes.append(rect) # Create patch collection with specified colour/alpha pc = PatchCollection(errorboxes, facecolor=facecolor, alpha=alpha, edgecolor=edgecolor) # Add collection to axes ax.add_collection(pc) # Plot errorbars artists = ax.errorbar(xdata, ydata, xerr=xerror, yerr=yerror, fmt='None', ecolor='k') return artists # Create figure and axes fig, ax = plt.subplots(1) # Call function to create error boxes _ = make_error_boxes(ax, x, y, xerr, yerr) plt.show() **Total running time of the script:** ( 0 minutes 0.021 seconds) .. only :: html .. container:: sphx-glr-footer .. container:: sphx-glr-download :download:`Download Python source code: errorbars_and_boxes.py ` .. container:: sphx-glr-download :download:`Download Jupyter notebook: errorbars_and_boxes.ipynb ` .. only:: html .. rst-class:: sphx-glr-signature `Gallery generated by Sphinx-Gallery `_