MTH 337: Week 5

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

Add text to figures using Matplotlib "text"

xpts = [1, 2, 1.5, 1]
ypts = [1, 1, 2, 1]
plt.plot(xpts, ypts)
plt.text(1.4, 1.4, 'Triangle');

fontsize

xpts = [1, 2, 1.5, 1]
ypts = [1, 1, 2, 1]
plt.plot(xpts, ypts)
plt.text(1.4, 1.4, 'Triangle', fontsize=20);

color

xpts = [1, 2, 1.5, 1]
ypts = [1, 1, 2, 1]
plt.plot(xpts, ypts)
plt.text(1.4, 1.4, 'Triangle', fontsize=20, color='r');

backgroundcolor

xpts = [1, 2, 1.5, 1]
ypts = [1, 1, 2, 1]
plt.plot(xpts, ypts)
plt.text(1.4, 1.4, 'Triangle', fontsize=20, color='r', backgroundcolor='lime');

weight

xpts = [1, 2, 1.5, 1]
ypts = [1, 1, 2, 1]
plt.plot(xpts, ypts)
plt.text(1.4, 1.4, 'Triangle', weight='bold');

Using different properties together

xpts = [1, 2, 1.5, 1]
ypts = [1, 1, 2, 1]
plt.plot(xpts, ypts)
plt.text(1.25, 1.2, 'Triangle', weight='bold', color='m', fontsize=32, backgroundcolor='y');

annotate

This adds text to a graph, and an arrow pointing from the text to some location. The keyword arguments are:

• xy: the location to be labeled, as an (x, y) tuple of coordinates.
• xytext: the location of the text, also as an (x, y) tuple of coordinates.
• s: the text to be added.
• arrowprops: a Python dictionary of {key:value} pairs, separated by commas. The keys are
  • arrowstyle
  • width
  • headwidth
  • headlength

Using the arrowstyle property

xpts = [1, 2, 1.5, 1]
ypts = [1, 1, 2, 1]
plt.plot(xpts, ypts)
plt.annotate(xy=(2, 1), xytext=(1.8, 1.1), s='vertex', arrowprops={'arrowstyle':'->'});

Specifying the arrow properties

xpts = [1, 2, 1.5, 1]
ypts = [1, 1, 2, 1]
plt.plot(xpts, ypts)
plt.annotate(xy=(2, 1), xytext=(1.8, 1.1), s='vertex', arrowprops={'width':1, 'headwidth': 5, 'headlength': 8});