Legends and annotations

Legends and annotations are effective tools to display information required to comprehend a plot in a glance. A typical plot will have the following additional information elements:

• A legend describing the various data series in the plot. This is provided by invoking the matplotlib legend() function and supplying the labels for each data series.

• Annotations for important points in the plot. The matplotlib annotate() function can be used for this purpose. A matplotlib annotation consists of a label and an arrow. This function has many parameters describing the label and arrow style and position, so you may need to call help(annotate) for a detailed description.

• Labels on the horizontal and vertical axes. These labels can be drawn by the xlabel() and ylabel() functions. We need to give these functions the text of the labels as a string and optional parameters such as the font size of the label.

• A descriptive title for the graph with the matplotlib title() function. Typically...