Placing Multiple Histograms in Figure with PyLab

Question

I have a short function as follows:

def drawChart(data,title):
    P.title(title)
    P.hist(data, bins=20, histtype='stepfilled')
    P.xlabel("Relevance")
    P.ylabel("Frequency")
    P.savefig(title + '.pdf')

This creates a pdf of my histogram. However I make around 6 calls to this, and would ideally like to save them all as one document.

Now firstly how do I collate them all and return an object from the drawChart for this to happen?

I have seen people use figure here

The first thing to do is to go here http://matplotlib.org/gallery.html and find whatever resembles what you want to do. — sashkello, Feb 04 '14 at 21:55
Do you want 6 plots in one figure (like http://matplotlib.org/examples/subplots_axes_and_figures/subplot_demo.html) or a 6 page pdf? — Jakob, Feb 04 '14 at 22:03

score 2 · Accepted Answer · answered Feb 04 '14 at 22:38

So you want subplots. A possible example could look like:

import numpy as np
import matplotlib.pyplot as plt
# create some data
data = np.random.rand(6,10)
fig, ax = plt.subplots(3,2)
ax = ax.reshape(6)
for ind, d in enumerate(data):
  ax[ind].hist(d)
fig.tight_layout()
plt.show()

which gives a figure like
enter image description here

More examples of subplots can be found in the matplotlib gallery, e.g. here.

Placing Multiple Histograms in Figure with PyLab

1 Answers1