[python] How to add title to subplots in Matplotlib?

I have one figure which contains many subplots.

fig = plt.figure(num=None, figsize=(26, 12), dpi=80, facecolor='w', edgecolor='k')
fig.canvas.set_window_title('Window Title')

# Returns the Axes instance
ax = fig.add_subplot(311) 
ax2 = fig.add_subplot(312) 
ax3 = fig.add_subplot(313) 

How do I add titles to the subplots?

fig.suptitle adds a title to all graphs and although ax.set_title() exists, the latter does not add any title to my subplots.

Thank you for your help.

Edit: Corrected typo about set_title(). Thanks Rutger Kassies

This question is related to python matplotlib plot subtitle

The answer is

ax.set_title() should set the titles for separate subplots:

import matplotlib.pyplot as plt

if __name__ == "__main__":
    data = [1, 2, 3, 4, 5]

    fig = plt.figure()
    fig.suptitle("Title for whole figure", fontsize=16)
    ax = plt.subplot("211")
    ax.set_title("Title for first plot")

    ax = plt.subplot("212")
    ax.set_title("Title for second plot")


Can you check if this code works for you? Maybe something overwrites them later?

A shorthand answer assuming import matplotlib.pyplot as plt:


as in:


Then there is no need for superfluous variables.

If you want to make it shorter, you could write :

import matplolib.pyplot as plt
for i in range(4):
    plt.subplot(2,2,i+1).set_title('Subplot n°{}' .format(i+1))

It makes it maybe less clear but you don't need more lines or variables

A solution I tend to use more and more is this one:

import matplotlib.pyplot as plt

fig, axs = plt.subplots(2, 2)  # 1
for i, ax in enumerate(axs.ravel()): # 2
    ax.set_title("Plot #{}".format(i)) # 3
  1. Create your arbitrary number of axes
  2. axs.ravel() converts your 2-dim object to a 1-dim vector in row-major style
  3. assigns the title to the current axis-object

In case you have multiple images and you want to loop though them and show them 1 by 1 along with titles - this is what you can do. No need to explicitly define ax1, ax2, etc.

  1. The catch is you can define dynamic axes(ax) as in Line 1 of code and you can set its title inside a loop.
  2. The rows of 2D array is length (len) of axis(ax)
  3. Each row has 2 items i.e. It is list within a list (Point No.2)
  4. set_title can be used to set title, once the proper axes(ax) or subplot is selected.
import matplotlib.pyplot as plt    
fig, ax = plt.subplots(2, 2, figsize=(6, 8))  
for i in range(len(ax)): 
    for j in range(len(ax[i])):
        ## ax[i,j].imshow(test_images_gr[0].reshape(28,28))
        ax[i,j].set_title('Title-' + str(i) + str(j))

fig, (ax1, ax2, ax3, ax4) = plt.subplots(nrows=1, ncols=4,figsize=(11, 7))

grid = plt.GridSpec(2, 2, wspace=0.2, hspace=0.5)

ax1 = plt.subplot(grid[0, 0])
ax2 = plt.subplot(grid[0, 1:])
ax3 = plt.subplot(grid[1, :1])
ax4 = plt.subplot(grid[1, 1:])

ax1.title.set_text('First Plot')
ax2.title.set_text('Second Plot')
ax3.title.set_text('Third Plot')
ax4.title.set_text('Fourth Plot')


enter image description here

Examples related to python

programming a servo thru a barometer Is there a way to view two blocks of code from the same file simultaneously in Sublime Text? python variable NameError Why my regexp for hyphenated words doesn't work? Comparing a variable with a string python not working when redirecting from bash script is it possible to add colors to python output? Get Public URL for File - Google Cloud Storage - App Engine (Python) Real time face detection OpenCV, Python xlrd.biffh.XLRDError: Excel xlsx file; not supported Could not load dynamic library 'cudart64_101.dll' on tensorflow CPU-only installation

Examples related to matplotlib

"UserWarning: Matplotlib is currently using agg, which is a non-GUI backend, so cannot show the figure." when plotting figure with pyplot on Pycharm How to increase image size of pandas.DataFrame.plot in jupyter notebook? How to create a stacked bar chart for my DataFrame using seaborn? How to display multiple images in one figure correctly? Edit seaborn legend How to hide axes and gridlines in Matplotlib (python) How to set x axis values in matplotlib python? How to specify legend position in matplotlib in graph coordinates Python "TypeError: unhashable type: 'slice'" for encoding categorical data Seaborn Barplot - Displaying Values

Examples related to plot

Fine control over the font size in Seaborn plots for academic papers Why do many examples use `fig, ax = plt.subplots()` in Matplotlib/pyplot/python Modify the legend of pandas bar plot Format y axis as percent Simple line plots using seaborn Plot bar graph from Pandas DataFrame Plotting multiple lines, in different colors, with pandas dataframe Plotting in a non-blocking way with Matplotlib What does the error "arguments imply differing number of rows: x, y" mean? matplotlib get ylim values

Examples related to subtitle

How to add title to subplots in Matplotlib? Use ffmpeg to add text subtitles