How to give the chart a legend

Once we start plotting more than one line of data points, things might become a little bit unclear. So by adding a legend to our graphs, we can tell which data is what, and what it actually means.

We do not have to choose different colors to represent the different data. Matplotlib automatically assigns a different color to each line of the data points.

All we have to do is create the chart and add a legend to it.

Getting ready

In this recipe, we will enhance the chart from the previous recipe, Placing labels on charts. We will only plot one chart.

How to do it…

First, we will plot more lines of data on the same chart, and then we will add a legend to the chart.

We'll do this by modifying the code from the previous recipe:

Matplotlib_chart_with_legend.py

    from matplotlib.figure import Figure 
    from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg 
    import tkinter as tk 
    #-------------------------------------------------------------- 
    fig ...