Legend placement options in Matplotlib - Step-by-Step Execution

Concept Flow - Legend placement options

Create plot with data

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Call plt.legend()

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Specify location parameter

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Legend placed on plot

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Show plot with legend

The flow shows creating a plot, calling legend with a location option, placing the legend accordingly, and displaying the plot.

Execution Sample

Matplotlib

import matplotlib.pyplot as plt
plt.plot([1,2,3], label='Line')
plt.legend(loc='upper right')
plt.show()

This code plots a line and places the legend at the upper right corner.

Execution Table

Step	Action	Parameter	Effect	Legend Position
1	Plot data	data=[1,2,3]	Line plotted	No legend yet
2	Call legend()	loc='upper right'	Legend created	Upper right corner
3	Show plot	None	Plot displayed with legend	Upper right corner
4	Call legend()	loc='lower left'	Legend moved	Lower left corner
5	Show plot	None	Plot displayed with legend	Lower left corner
6	Call legend()	loc='best'	Legend auto-placed	Best location chosen by matplotlib
7	Show plot	None	Plot displayed with legend	Best location
8	Call legend()	loc='center'	Legend centered	Center of plot
9	Show plot	None	Plot displayed with legend	Center
10	Call legend()	loc='right'	Legend placed on right	Right side
11	Show plot	None	Plot displayed with legend	Right side
12	Call legend()	loc='none'	No legend shown	No legend
13	Show plot	None	Plot displayed without legend	No legend

💡 All legend placement options demonstrated and plot shown accordingly.

Variable Tracker

Variable	Start	After Step 2	After Step 4	After Step 6	After Step 8	After Step 10	After Step 12
legend_location	None	'upper right'	'lower left'	'best'	'center'	'right'	'none'

Key Moments - 3 Insights

Why does the legend sometimes overlap the plot lines?

When using fixed locations like 'center', the legend can cover data. Using 'best' lets matplotlib find a place with least overlap, as shown in execution_table rows 6 and 7.

What happens if I set loc='none'?

No legend is shown on the plot, as seen in execution_table rows 12 and 13 where the legend disappears.

How can I place the legend on the right side of the plot?

Using loc='right' places the legend on the right side of the plot, demonstrated in rows 10 and 11.

Visual Quiz - 3 Questions

Look at the execution_table, what is the legend position after step 4?

A Upper right corner

B Lower left corner

C Center of plot

D No legend

💡 Hint

Check the 'Legend Position' column for step 4 in execution_table.

At which step does matplotlib automatically choose the best legend location?

A Step 2

B Step 8

C Step 6

D Step 10

💡 Hint

Look for 'best' in the 'Parameter' column in execution_table.

If you want no legend to appear, which loc value should you use according to the table?

A 'none'

B 'best'

C 'upper right'

D 'right'

💡 Hint

Check the effect of loc='none' in execution_table rows 12 and 13.

Concept Snapshot

plt.legend(loc=location) places the legend.
Common loc values: 'upper right', 'lower left', 'best', 'center', 'right'.
'best' auto-finds a clear spot.
'none' hides the legend.
Legend can be inside or outside the plot area.

Full Transcript

This lesson shows how to place legends in matplotlib plots using the loc parameter in plt.legend(). We start by plotting data, then call plt.legend() with different loc values like 'upper right', 'lower left', 'best', 'center', and 'right'. Each placement changes where the legend appears on the plot. The 'best' option lets matplotlib pick a spot that avoids covering data. Using 'none' hides the legend. The execution table traces each step showing the legend's position. Variable tracker shows how the legend_location changes. Key moments clarify common confusions like overlapping legends and placing legends on the right side of the plot. The quiz tests understanding of legend positions at different steps. The snapshot summarizes how to use legend placement options simply.