Save multiple figures in one pdf page, matplotlib

Question

I'm trying to get my figures in just one pdf page, but I don't know how to do this. I found out that it's possible to save multiple figures in a pdf file with 'matplotlib.backends.backend_pdf', but it doesn't work for just one page. Has anyone any ideas ? Convert the figures to just one figure ?

Answer 1

You can use matplotlib gridspec to have multiple plots in 1 window

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

from matplotlib.gridspec import GridSpec
import random
import numpy
from matplotlib import pyplot as pl

fig = pl.figure(figsize=(12, 16))
G = GridSpec(2,2)   
axes_1 = pl.subplot(G[0, :])

x = [random.gauss(3,1) for _ in range(400)]
bins = numpy.linspace(-10, 10, 100)
axes_1.hist(x, bins, alpha=0.5, label='x')

axes_2 = pl.subplot(G[1, :])
axes_2.plot(x)

pl.tight_layout()
pl.show()

You can change the rows and column values and can subdivide the sections.

Answer 2

Here is a solution provided by matplotlib:

from matplotlib.backends.backend_pdf import PdfPages
import matplotlib.pyplot as plt

with PdfPages('foo.pdf') as pdf:
    #As many times as you like, create a figure fig and save it:
    fig = plt.figure()
    pdf.savefig(fig)

    ....
    fig = plt.figure()
    pdf.savefig(fig) 

Voilà

Find a full example here: multipage pdf matplotlib

And by the way, for one figure, you don't need matplotlib.backends.backend_pdf just add pdf extension like so:

plt.savefig("foo.pdf")

Answer 3

The PDF backend makes one page per figure. Use subplots to get multiple plots into one figure and they'll all show up together on one page of the PDF.