Add perpendicular caps to error bars in Matplotlib

Prerequisites: Matplotlib

The errorbar() function in pyplot module of matplotlib library is used to plot y versus x as lines and/or markers with attached errorbars. For our requirement we need to specifically focussing on capsize attribute of this function. Simply providing a value to it will produce our required functionality.

Syntax: matplotlib.pyplot.errorbar(x, y, yerr=None, xerr=None, fmt=”, ecolor=None, elinewidth=None, capsize=None, barsabove=False, lolims=False, uplims=False, xlolims=False, xuplims=False, errorevery=1, capthick=None, \*, data=None, \*\*kwargs)

Parameters: This method accept the following parameters that are described below:

• x, y: These parameters are the horizontal and vertical coordinates of the data points.
• fmt: This parameter is an optional parameter and it contains the string value.
• capsize: This parameter is also an optional parameter. And it is the length of the error bar caps in points with default value NONE.
• barsabove: This parameter is also an optional parameter. It contains boolean value True for plotting errorsbars above the plot symbols.Its default value is False.
• errorevery: This parameter is also an optional parameter. They contain integer values which is used to draw error bars on a subset of the data.

Approach

• Import module
• Create data
• Provide error values
• Pass all the values to errorbar() function along with capsize attribute and its value
• Display plot

Example 1:

Python3

import matplotlib.pyplot as plt

x_values = [5, 4, 3, 2, 1]
y_values = [8, 4, 9, 1, 0]

y_error = [0, 0.3, 1, 0.2, 0.75]

plt.errorbar(x_values, y_values,  yerr=y_error,
             fmt='o', markersize=8, capsize=10)

plt.show()

Output:

Example 2:

Python3

import matplotlib.pyplot as plt

x_values = [0, 1, 2, 3, 4, 5]
y_values = [8, 4, 9, 1, 0, 5]

plt.plot(x_values, y_values)
x_error = [0, 0.3, 1, 0.2, 0.75, 2]

plt.errorbar(x_values, y_values,  xerr=x_error,
             fmt='o', markersize=8, capsize=6, color="r")

plt.show()

Output:

Example 3: 

Python3

import matplotlib.pyplot as plt

x_values = [0, 1, 2, 3, 4, 5]
y_values = [8, 4, 9, 1, 0, 5]


x_error = [0, 0.3, 1, 0.2, 0.75, 2]
y_error = [0.3, 0.3, 2, 0.5, 0.7, 0.6]

plt.errorbar(x_values, y_values,  xerr=x_error, yerr=y_error,
             fmt='D', markersize=8, capsize=3, color="r")

plt.show()

Output: