Matplotlib Axes Class

An Axes object is an image area with a data space. A given figure can contain many axes, but a given Axes object can only be in one figure. Axes contain two (or3Three Axis objects in case D. The Axes class and its member functions are the main entry points for the OO interface.

By calling the add_axes() method, an Axes object is added to the figure. It returns the axis object and adds an axis at the position rect [left, bottom, width, height], where all quantities are fractions of the width and height of the figure.

Parameter

The following are the parameters of the Axes class -

rect - 4a sequence of [left, bottom, width, height] quantities.

　# Filename : example.py
# Copyright :　2020 By w3codebox
# Author by : www.oldtoolbag.com
# Date :　2020-08-08
ax = fig.add_axes([0,0,1,1])

Example

The legend() method of the axes class adds a legend to the plotting graph. It requires three parameters. -

# Filename : example.py
# Copyright :　2020 By w3codebox
# Author by : www.oldtoolbag.com
# Date :　2020-08-08
ax.legend(handles, labels, loc)

where label is a series of strings, processing a series of Line2D or Patch instance. loc can be a string or integer specifying the legend position.

axes.plot()

This is a basic method of the axis class, which draws the values of one array against another array as a line or marker. The plot() method can have an optional format string parameter to specify the color, style, and size of the line and marker.

Color code

Marker code

Line style

The following example displays the advertising expenses and sales figures of television and smartphones in the form of a line chart. The line representing television is a solid line with yellow and square markers, while the smartphone line is a dashed line with green and circular markers.

Reference Implementation Code -

# Filename : example.py
# Copyright :　2020 By w3codebox
# Author by : www.oldtoolbag.com
# Date :　2020-08-08
#!　/usr/bin/env python
　#coding=utf-8
　import matplotlib.pyplot as plt
　# Display Chinese settings...
　plt.rcParams['font.sans-serif'] = ['SimHei']  # Step one (replace sans-serif font)
　plt.rcParams['axes.unicode_minus'] = False  # Step two (solve the problem of displaying negative signs on the axis)
　y = [1,　4,　9,　16,　25,36,49,　64]
　x1　= [1,　16,　30,　42,55,　68,　77,88]
　x2　= [1,6,12,18,28,　40,　52,　65]
　fig = plt.figure()
　ax = fig.add_axes([0,0,1,1])
　l1　= ax.plot(x1,y,'ys-')  # solid line with yellow colour and square marker
　l2　= ax.plot(x2,y,'go--')  # dash line with green colour and circle marker
　ax.legend(labels=('Television', 'Smartphone'), loc='upper left')  # legend placed at lower right
　ax.set_title("The Impact of Advertising on Sales")
　ax.set_xlabel('Medium')
　ax.set_ylabel('Sales')
　plt.show()

Execute the above example code to get the following results -