Python - Stacking two histograms with a scatter plot

Question

Having an example code for a scatter plot along with their histograms

x = np.random.rand(5000,1)
y = np.random.rand(5000,1)



fig = plt.figure(figsize=(7,7))
ax = fig.add_subplot(111)
ax.scatter(x, y, facecolors='none')
ax.set_xlim(0,1)
ax.set_ylim(0,1)



fig1 = plt.figure(figsize=(7,7))
ax1 = fig1.add_subplot(111)
ax1.hist(x, bins=25, fill = None, facecolor='none', 
        edgecolor='black', linewidth = 1)



fig2 = plt.figure(figsize=(7,7))
ax2 = fig2.add_subplot(111)
ax2.hist(y, bins=25 , fill = None, facecolor='none', 
        edgecolor='black', linewidth = 1)

What I'm wanting to do is to create this graph with the histograms attached to their respected axis almost like this example

I'm familiar with stacking and merging the x-axis

f, (ax1, ax2, ax3) = plt.subplots(3)
ax1.scatter(x, y)
ax2.hist(x, bins=25, fill = None, facecolor='none', 
        edgecolor='black', linewidth = 1)
ax3.hist(y, bins=25 , fill = None, facecolor='none', 
        edgecolor='black', linewidth = 1)

f.subplots_adjust(hspace=0)
plt.setp([a.get_xticklabels() for a in f.axes[:-1]], visible=False)

But I have no idea how to attach the histograms to the y axis and x axis like in the picture I posted above, and on top of that, how to vary the size of the graphs (ie make the scatter plot larger and the histograms smaller in comparison)

Answer 1

Seaborn is the way to go for quick statistical plots. But if you want to avoid another dependency you can use subplot2grid to place the subplots and the keywords sharex and sharey to make sure the axes are synchronized.

import numpy as np
import matplotlib.pyplot as plt

x = np.random.randn(100)
y = np.random.randn(100)

scatter_axes = plt.subplot2grid((3, 3), (1, 0), rowspan=2, colspan=2)
x_hist_axes = plt.subplot2grid((3, 3), (0, 0), colspan=2,
                               sharex=scatter_axes)
y_hist_axes = plt.subplot2grid((3, 3), (1, 2), rowspan=2,
                               sharey=scatter_axes)

scatter_axes.plot(x, y, '.')
x_hist_axes.hist(x)
y_hist_axes.hist(y, orientation='horizontal')

You should always look at the matplotlib gallery before asking how to plot something, chances are that it will save you a few keystrokes -- I mean you won't have to ask. There are actually two plots like this in the gallery. Unfortunately the code is old and does not take advantage of subplot2grid, the first one uses rectangles and the second one uses axes_grid, which is a somewhat weird beast. That's why I posted this answer.