Legends and annotations

Legends are an important element that is used to identify the plot elements in a figure. The easiest way to show a legend inside a figure is to use the label argument of the plot function, and show the labels by calling the plt.legend() method:

>>> x = np.linspace(0, 1, 20) 
>>> y1 = np.sin(x)
>>> y2 = np.cos(x)
>>> y3 = np.tan(x)
>>> plt.plot(x, y1, 'c', label='y=sin(x)')
>>> plt.plot(x, y2, 'y', label='y=cos(x)')
>>> plt.plot(x, y3, 'r', label='y=tan(x)')
>>> plt.lengend(loc='upper left')
>>> plt.show()

The output for the preceding command as follows:

The loc argument in the legend command is used to figure out the position of the label box. There are several valid location options: lower left, right, upper left, lower center, upper right, center, lower right, upper right, center right, best, upper center, and center left. The default position setting is upper right. However, when we...