将多个 pdf 文件中的特定页面写入新的 pdf 文件

Question

I have multiple pdf files that I want to extract a group of specific pages from where each set of pages is different for each pdf file. I have created a dictionary with the keys as the pdf file name and the values as the list of pages to be extracted from each pdf file (shown as key). I intend to extract the given pages from the associated pdf file and write them all to one new pdf file so that I can do data extraction on this final file. I have tried PyPDF4 as well as FPDF but no joy as yet as it gives me either a large pdf with blank pages or a pdf with just 1 or 2 pages extracted or error that the pdf object cannot be found. I am hoping to get some guidance on where I am going wrong with my approach. Below is my code:

import PyPDF4
from PyPDF4 import PdfFileReader, PdfFileWriter

for pdf,pgs in dic_11_1.items():
  pdf=list(dic_11_1.keys())
  pgs=list(dic_11_1.values())
  for i in range(0,len(pdf)):
    pages = pgs[i]
    object = open(pdf[i],'rb') 
    pdfinput=PyPDF4.PdfFileReader(object,'rb')
    if pdfinput.isEncrypted:
        pdfinput.decrypt('')
    else:
        pdfinput
    for p in pages:
        page=pdfinput.getPage(p)
        pdf_writer=PyPDF4.PdfFileWriter()
        pdf_writer.addPage(page)
        with open('F111.pdf',mode='wb') as output:
            pdf_writer.write(output)

Answer 1

Well, the problem is you're not iterating properly. See comments in code for better understanding.

from PyPDF4 import PdfFileReader, PdfFileWriter

dic_11_1 = {
    'filename1.pdf': [1, 3, 4],
    'filename2.pdf': [0, 2, 3],
}
# note pages are zero-numbered

# you need single writer for all files, don't declare it in a loop
pdf_writer = PdfFileWriter()

for filename, pages in dic_11_1.items():
    # now you have filename and pages set to 'filename1.pdf' and [1, 3, 4]
    # on second iteration they'll be set to 'filename2.pdf' and [0, 2, 3]
    # ...

    # don't use `object` as variable name: it's valid, but bad style
    # (it shadows builtin `object`)
    # context manager will close the file automatically
    with open(filename,'rb') as src:
        pdfinput = PdfFileReader(src, 'rb')

        if pdfinput.isEncrypted:
            pdfinput.decrypt('')
            # you don't need empty `else`

        for p in pages:
            # you might want to use `p - 1` instead if your input was 1-numbered
            page = pdfinput.getPage(p)
            pdf_writer.addPage(page)

# when all pages are added, write to output
with open('F111.pdf',mode='wb') as output:
    pdf_writer.write(output)