Matplotlib.axes.Axes.add_collection() in Python

Last Updated : 12 Jul, 2025

Matplotlib is a library in Python and it is numerical - mathematical extension for NumPy library. The Axes Class contains most of the figure elements: Axis, Tick, Line2D, Text, Polygon, etc., and sets the coordinate system. And the instances of Axes supports callbacks through a callbacks attribute.

matplotlib.axes.Axes.add_collection() Function

The Axes.add_collection() function in axes module of matplotlib library is used to add a Collection to the axes' collections; return the collection.

Syntax: Axes.add_collection(self, collection, autolim=True) Parameters: This method accepts the following parameters.

collection: This parameter is the collection which is produced by collection() function .

Return value: This method returns the collection.

Below examples illustrate the matplotlib.axes.Axes.add_collection() function in matplotlib.axes: Example 1:

Python3

# Implementation of matplotlib function
import matplotlib.pyplot as plt
from matplotlib.collections import EventCollection
import numpy as np

np.random.seed(19680801)
xvalue = np.random.random([2, 10])
xvalue1 = xvalue[0, :]
xvalue2 = xvalue[1, :]
xvalue1.sort()
xvalue2.sort()

yvalue1 = xvalue1 ** 4
yvalue2 = 1 - xvalue2 ** 6

fig = plt.figure()
ax = fig.add_subplot(1, 1, 1)
ax.plot(xvalue1, yvalue1, color ='tab:blue')
ax.plot(xvalue2, yvalue2, color ='tab:green')

xresult1 = EventCollection(xvalue1, color ='tab:blue')
xresult2 = EventCollection(xvalue2, color ='tab:green')
yresult1 = EventCollection(yvalue1, color ='tab:blue',
                           orientation ='vertical')
yresult2 = EventCollection(yvalue2, color ='tab:green',
                           orientation ='vertical')
ax.add_collection(xresult1)
ax.add_collection(xresult2)
ax.add_collection(yresult1)
ax.add_collection(yresult2)

ax.set_xlim([0, 1])
ax.set_ylim([0, 1])

fig.suptitle('matplotlib.axes.Axes.add_collection() \
function Example\n\n', fontweight ="bold")
plt.show()

Output:

Example 2:

Python3

# Implementation of matplotlib function
import matplotlib.pyplot as plt
from matplotlib.collections import LineCollection
from matplotlib import colors as mcolors
import numpy as np

N = 50
x = np.arange(N)

ys = [i/(x + 1) for i in x]

fig, ax = plt.subplots()
ax.set_xlim(0, 20)
ax.set_ylim(0, 20)

line_segments = LineCollection([np.column_stack([x, y]) for y in ys],
                               linewidths =(0.5, 1, 1.5, 2),
                               linestyles ='dashed', 
                               color ="# eeffdd")
line_segments.set_array(x**2)
ax.add_collection(line_segments)

fig.suptitle('matplotlib.axes.Axes.add_collection()\
 function Example\n\n', fontweight ="bold")
plt.show()