将多个绘图保存到一个 pdf 文件

Question

I am trying to save multiple plots in one pdf file.

can anyone help with the following code?

what is wrong with this code:

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


pdfFile = PdfPages("output.pdf")

for i in range(10):
    xVals = [x for x in range(20)]
    yVals = [rand.randint(50,100) for x in xVals]
    plt.figure(figsize=(20,10))
    fig = plt.plot(xVals , yVals)
    plt.xlabel('Data point') 
    plt.ylabel('Strain [us]') 
    plt.title(i)

    #plt.show()

    pdfFile.savefig(fig)
    print(i)

pdfFile.close()

Answer 1

plot returns as list of Line2D s (in your case just one). From this line you need to get the figure using get_figure :

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


pdfFile = PdfPages("output.pdf")

for i in range(10):
    xVals = [x for x in range(20)]
    yVals = [rand.randint(50,100) for x in xVals]
    plt.figure(figsize=(20,10))
    line, = plt.plot(xVals , yVals)
    plt.xlabel('Data point') 
    plt.ylabel('Strain [us]') 
    plt.title(i)

    #plt.show()

    pdfFile.savefig(line.get_figure())
    print(i)

pdfFile.close()

When no figure is specified in savefig the current figure is saved, so you could also simply write:

plt.plot(xVals , yVals)
pdfFile.savefig()