Spread the love

Learn how to make beautiful GUI apps

Comprehensive, for Kivy beginners, easy to follow.

Get the book here (PDF) or on Amazon:

ebook / paperback (black and white) / paperback (full color)

In this part of the Matplotlib series we’ll be talking about axis ranges. Let’s start by plotting a function:

In [1]:

%matplotlib inline
import matplotlib as mpl
import matplotlib.pyplot as plt
import numpy as np

x = np.linspace(-10, 10, 100)
y = np.sin(x) / x

fig, ax = plt.subplots()

ax.plot(x, y)

Out[1]:

[<matplotlib.lines.Line2D at 0x222eaa55048>]

X AND Y AXIS LIMITS

As you can see, the axis ranges are adjusted for us automatically to fit the data: from -10.0 to 10.0 on the X axis and from -0.2 to 1.0 on the Y axis. But we can explicitly set the axis ranges for each axis using the set_xlim and set_ylim methods respectively. You pass the lower and upper limit to either method. Have a look:

In [2]:

fig, ax = plt.subplots()
ax.plot(x, y)

# The X range should be from -5 to 5 because we're only interested in the middle part of the graph.
ax.set_xlim(-5, 5)

Out[2]:

(-5, 5)

In [3]:

fig, ax = plt.subplots()
ax.plot(x, y)

# And now the Y range should be from -0.2 to 0.2 because we're only interested in the lower part of the graph.
ax.set_ylim(-0.2, 0.2)

Out[3]:

(-0.2, 0.2)

In [4]:

fig, ax = plt.subplots()
ax.plot(x, y)

# This time we'll set both X and Y axis limits so that the graph is smaller in size.
ax.set_xlim(-15, 15)
ax.set_ylim(-1, 3)