How to set font size of Matplotlib axis Legend?

Question

I have a code like this:

import matplotlib.pyplot as plt
from matplotlib.pyplot import *
from matplotlib.font_manager import FontProperties

fontP = FontProp         


        

Answer 1

Inspired by the current top answer, I found a slightly more natural way to change the fontsizes in the legend. The fontsize argument sets the font size of each of the data labels, and the title_fontsize argument sets the fontsize of the title, if you give the legend a title.

import matplotlib.pyplot as plt
fig, ax = plt.subplots()
ax.plot([0,1,2],[2,1,2],label='test_data (fs=12)')
ax.legend(fontsize=12, title='TITLE (fs=30)',title_fontsize=30)

Gives a figure like this: