[matplotlib] Giving graphs a subtitle in matplotlib

I want to give my graph a title in big 18pt font, then a subtitle below it in smaller 10pt font. How can I do this in matplotlib? It appears the title() function only takes one single string with a single fontsize attribute. There has to be a way to do this, but how?

Although this doesn't give you the flexibility associated with multiple font sizes, adding a newline character to your pyplot.title() string can be a simple solution;

plt.title('Really Important Plot\nThis is why it is important')

This is a pandas code example that implements Floris van Vugt's answer (Dec 20, 2010). He said:

>What I do is use the title() function for the subtitle and the suptitle() for the >main title (they can take different fontsize arguments). Hope that helps!

import pandas as pd
import matplotlib.pyplot as plt

d = {'series a' : pd.Series([1., 2., 3.], index=['a', 'b', 'c']),
      'series b' : pd.Series([1., 2., 3., 4.], index=['a', 'b', 'c', 'd'])}
df = pd.DataFrame(d)

title_string = "This is the title"
subtitle_string = "This is the subtitle"

plt.figure()
df.plot(kind='bar')
plt.suptitle(title_string, y=1.05, fontsize=18)
plt.title(subtitle_string, fontsize=10)

Note: I could not comment on that answer because I'm new to stackoverflow.

Just use TeX ! This works :

title(r"""\Huge{Big title !} \newline \tiny{Small subtitle !}""")

EDIT: To enable TeX processing, you need to add the "usetex = True" line to matplotlib parameters:

fig_size = [12.,7.5]
params = {'axes.labelsize': 8,
      'text.fontsize':   6,
      'legend.fontsize': 7,
      'xtick.labelsize': 6,
      'ytick.labelsize': 6,
      'text.usetex': True,       # <-- There 
      'figure.figsize': fig_size,
      }
rcParams.update(params)

I guess you also need a working TeX distribution on your computer. All details are given at this page:

http://matplotlib.org/users/usetex.html

As mentioned here, uou can use matplotlib.pyplot.text objects in order to achieve the same result:

plt.text(x=0.5, y=0.94, s="My title 1", fontsize=18, ha="center", transform=fig.transFigure)
plt.text(x=0.5, y=0.88, s= "My title 2 in different size", fontsize=12, ha="center", transform=fig.transFigure)
plt.subplots_adjust(top=0.8, wspace=0.3)

What I do is use the title() function for the subtitle and the suptitle() for the main title (they can take different fontsize arguments). Hope that helps!

The solution that worked for me is:

• use suptitle() for the actual title
• use title() for the subtitle and adjust it using the optional parameter y:

    import matplotlib.pyplot as plt
    """
            some code here
    """
    plt.title('My subtitle',fontsize=16)
    plt.suptitle('My title',fontsize=24, y=1)
    plt.show()

There can be some nasty overlap between the two pieces of text. You can fix this by fiddling with the value of y until you get it right.