倒序排列

from  PyPDF2  import  PdfFileWriter,PdfFileReader
读pdf=PdfFileReader(r"E:pdfpython.pdf")
写pdf=PdfFileWriter()
for  page  in  range(读pdf.getNumPages()-1,-1,-1):
    写pdf.addPage(读pdf.getPage(page))

with  open(r"E:pdf给页码排序.pdf","wb")  as  f:
    写pdf.write(f)