Splits a given PDF file into separate PDFs made up of the odd and even pages

split_pdf.py

from PyPDF2 import PdfFileReader, PdfFileWriter
import sys

# Splits a given PDFfile into two odd and even page'd PDFs
# Also flips the even pages upside down and reverses their order

# This is to faciliate double-sided printing without having the printer support it
# If there's an odd number of pages, the last page is placed separately in a third PDF
# This helps make it easier to re-feed the paper without worrying about that remainder page

try:
    target = sys.argv[1]
except:
    print("Provide pdf file to split")

pdf_reader = PdfFileReader(open(target, 'rb'))
pages_count = pdf_reader.getNumPages()

odd_writer  = PdfFileWriter()
even_writer = PdfFileWriter()
last_page = PdfFileWriter()

even_outs = []

hasLast = False

for page_num in range(0, pages_count, 2):
    next_num = page_num + 1
    if next_num >= pages_count:
        # unmatched odd page!!! stands alone
        last_page.addPage(pdf_reader.getPage(page_num))
        hasLast = True
        break
    odd_writer.addPage(pdf_reader.getPage(page_num))
    even_outs.append(pdf_reader.getPage(next_num))

for page in even_outs[::-1]:
    page.rotateClockwise(180)
    even_writer.addPage(page)

with open(f"{target}_odd.pdf",'wb') as out:
    odd_writer.write(out)

with open(f"{target}_even.pdf",'wb') as out:
    even_writer.write(out)

if hasLast:
    with open(f"{target}_last.pdf", 'wb') as out:
        last_page.write(out)