Matplotlib.pyplot.annotate() in Python

Last Updated : 12 Apr, 2020

Matplotlib is a library in Python and it is numerical - mathematical extension for NumPy library. Pyplot is a state-based interface to a Matplotlib module which provides a MATLAB-like interface.

matplotlib.pyplot.annotate() Function

The annotate() function in pyplot module of matplotlib library is used to annotate the point xy with text s.

Syntax: angle_spectrum(x, Fs=2, Fc=0, window=mlab.window_hanning, pad_to=None, sides='default', **kwargs) Parameters: This method accept the following parameters that are described below:

s: This parameter is the text of the annotation.

xy: This parameter is the point (x, y) to annotate.

xytext: This parameter is an optional parameter. It is The position (x, y) to place the text at.

xycoords: This parameter is also an optional parameter and contains the string value.

textcoords: This parameter contains the string value.Coordinate system that xytext is given, which may be different than the coordinate system used for xy

arrowprops : This parameter is also an optional parameter and contains dict type.Its default value is None.

annotation_clip : This parameter is also an optional parameter and contains boolean value.Its default value is None which behaves as True.

Returns: This method returns the annotation.

Below examples illustrate the matplotlib.pyplot.annotate() function in matplotlib.pyplot: Example #1:

# Implementation of matplotlib.pyplot.annotate()
# function

import matplotlib.pyplot as plt
import numpy as np


fig, geeeks = plt.subplots()

t = np.arange(0.0, 5.0, 0.001)
s = np.cos(3 * np.pi * t)
line = geeeks.plot(t, s, lw = 2)

# Annotation
geeeks.annotate('Local Max', xy =(3.3, 1),
                xytext =(3, 1.8), 
                arrowprops = dict(facecolor ='green',
                                  shrink = 0.05),)

geeeks.set_ylim(-2, 2)

# Plot the Annotation in the graph
plt.show()

Output:

Example #2:

# Implementation of matplotlib.pyplot.annotate()
# function

import numpy as np
import matplotlib.pyplot as plt

x = np.arange(0, 10, 0.005)
y = np.exp(-x / 3.) * np.sin(3 * np.pi * x)

fig, ax = plt.subplots()
ax.plot(x, y)
ax.set_xlim(0, 10)
ax.set_ylim(-1, 1)

# Setting up the parameters
xdata, ydata = 5, 0
xdisplay, ydisplay = ax.transData.transform((xdata, ydata))

bbox = dict(boxstyle ="round", fc ="0.8")
arrowprops = dict(
    arrowstyle = "->",
    connectionstyle = "angle, angleA = 0, angleB = 90,\
    rad = 10")

offset = 72

# Annotation
ax.annotate('data = (%.1f, %.1f)'%(xdata, ydata),
            (xdata, ydata), xytext =(-2 * offset, offset),
            textcoords ='offset points',
            bbox = bbox, arrowprops = arrowprops)


disp = ax.annotate('display = (%.1f, %.1f)'%(xdisplay, ydisplay),
            (xdisplay, ydisplay), xytext =(0.5 * offset, -offset),
            xycoords ='figure pixels',
            textcoords ='offset points',
            bbox = bbox, arrowprops = arrowprops)

# To display the annotation
plt.show()