142

plotting module

def plotGraph(X,Y):
    fignum = random.randint(0,sys.maxint)
    plt.figure(fignum)
    ### Plotting arrangements ###
    return fignum

main module

import matplotlib.pyplot as plt
### tempDLStats, tempDLlabels are the argument
plot1 = plotGraph(tempDLstats, tempDLlabels)
plot2 = plotGraph(tempDLstats_1, tempDLlabels_1)
plot3 = plotGraph(tempDLstats_2, tempDLlabels_2)
plt.show()

I want to save all the graphs plot1, plot2, plot3 to a single PDF file. Is there any way to achieve it? I can't include the plotGraph function in the main module.

There's a function named pyplot.savefig but that seems to work only with a single figure. Is there any other way to accomplish it?

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1
  • I provide a solution to essentially an identical question here: stackoverflow.com/questions/38938454/… fyi to all; it may be of interest, provides versatile template code with lots of demonstrated customization of number of subplots per page, the spacing between them, overall style, etc., using PdfPages from matplotlib and optionally a more advanced code template leveraging seaborn Commented Nov 23, 2021 at 8:39

4 Answers 4

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282

If someone ends up here from google, looking to convert a single figure to a .pdf (that was what I was looking for):

import matplotlib.pyplot as plt

f = plt.figure()
plt.plot(range(10), range(10), "o")
plt.show()

f.savefig("foo.pdf", bbox_inches='tight')
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Comments

171

For multiple plots in a single pdf file you can use PdfPages

In the plotGraph function you should return the figure and than call savefig of the figure object.

------ plotting module ------

def plotGraph(X,Y):
      fig = plt.figure()
      ### Plotting arrangements ###
      return fig

------ plotting module ------

----- mainModule ----

from matplotlib.backends.backend_pdf import PdfPages

plot1 = plotGraph(tempDLstats, tempDLlabels)
plot2 = plotGraph(tempDLstats_1, tempDLlabels_1)
plot3 = plotGraph(tempDLstats_2, tempDLlabels_2)

pp = PdfPages('foo.pdf')
pp.savefig(plot1)
pp.savefig(plot2)
pp.savefig(plot3)
pp.close()
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3 Comments

"Plotting Arrangements" deserves an example to explain how to actually add plots to figures!
@user2127595 This works for me: def plot_graph(x, y1, y2): fig = plt.figure() axes1 = fig.add_subplot(2, 1, 1) axes2 = fig.add_subplot(2, 1, 2) axes1.plot(x, y1) axes2.plot(x, y2) return fig
I am not sure why this answer didn't get the deserved attention: it answers the question straight to the point.
43

Here is the canonical example provided by the matplotlib documentation site:

import datetime
import numpy as np
from matplotlib.backends.backend_pdf import PdfPages
import matplotlib.pyplot as plt

# Create the PdfPages object to which we will save the pages:
# The with statement makes sure that the PdfPages object is closed properly at
# the end of the block, even if an Exception occurs.
with PdfPages('multipage_pdf.pdf') as pdf:
    plt.figure(figsize=(3, 3))
    plt.plot(range(7), [3, 1, 4, 1, 5, 9, 2], 'r-o')
    plt.title('Page One')
    pdf.savefig()  # saves the current figure into a pdf page
    plt.close()

    plt.rc('text', usetex=True)
    plt.figure(figsize=(8, 6))
    x = np.arange(0, 5, 0.1)
    plt.plot(x, np.sin(x), 'b-')
    plt.title('Page Two')
    pdf.savefig()
    plt.close()

    plt.rc('text', usetex=False)
    fig = plt.figure(figsize=(4, 5))
    plt.plot(x, x*x, 'ko')
    plt.title('Page Three')
    pdf.savefig(fig)  # or you can pass a Figure object to pdf.savefig
    plt.close()

    # We can also set the file's metadata via the PdfPages object:
    d = pdf.infodict()
    d['Title'] = 'Multipage PDF Example'
    d['Author'] = u'Jouni K. Sepp\xe4nen'
    d['Subject'] = 'How to create a multipage pdf file and set its metadata'
    d['Keywords'] = 'PdfPages multipage keywords author title subject'
    d['CreationDate'] = datetime.datetime(2009, 11, 13)
    d['ModDate'] = datetime.datetime.today()
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1 Comment

If you are using plt.show() put it after pdf.savefig().
-40

Never mind got the way to do it. 

def plotGraph(X,Y):
     fignum = random.randint(0,sys.maxint)
     fig = plt.figure(fignum)
     ### Plotting arrangements ###
     return fig

------ plotting module ------

----- mainModule ----

 import matplotlib.pyplot as plt
 ### tempDLStats, tempDLlabels are the argument
 plot1 = plotGraph(tempDLstats, tempDLlabels)
 plot2 = plotGraph(tempDLstats_1, tempDLlabels_1)
 plot3 = plotGraph(tempDLstats_2, tempDLlabels_2)
 plt.show()
 plot1.savefig('plot1.png')
 plot2.savefig('plot2.png')
 plot3.savefig('plot3.png')

----- mainModule -----

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3 Comments

Wait, I thought you wanted to save the plots into a single PDF file. Your solution saves the images into three separate PNG files, which seems like the answer to a different question.
Extremely sorry. I was conentrating more on saving the file somehow. I knew about the backend pdf thing..but got on with my work and neglected to add it. Anyway, thanks for pointing it out.
Seeing the number of downvotes, you may think about deleting this answer to leave "room" for the other answers.

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