如何使用pyPdf反转PDF文件中页面的顺序？

Question

我有一个PDF文件叫“myFile.pdf”。我想用pyPdf这个工具，把它的页面顺序反过来，应该怎么做呢？

Answer 1

截至2019年1月（其实早在这之前），pyPdf这个库就不再更新了，经过测试发现它和（至少）Python 3.6不兼容，可能和Python 3根本就不兼容：

In [1]: import pyPdf
---------------------------------------------------------------------------
ModuleNotFoundError                       Traceback (most recent call last)
<ipython-input-1-bba5a42e9137> in <module>
----> 1 import pyPdf

c:\temp\envminecart\lib\site-packages\pyPdf\__init__.py in <module>
----> 1 from pdf import PdfFileReader, PdfFileWriter
      2 __all__ = ["pdf"]

ModuleNotFoundError: No module named 'pdf'

（把__all__的赋值放在import语句上面可以解决这个具体的问题，但由于Python 2的语法，其他的SyntaxError错误又会出现。）

幸运的是，它的继任者项目，PyPDF2，在Python 3.6（至少）上运行得很好。看起来它的核心用户接口故意保持了和pyPdf的兼容性，所以在现代Python中可以使用nosklo的回答，只需在pip install PyPDF2后，将import语句中的pyPdf改为PyPDF2，并把xrange换成range：

from PyPDF2 import PdfFileWriter, PdfFileReader
output_pdf = PdfFileWriter()

with open(r'input.pdf', 'rb') as readfile:
    input_pdf = PdfFileReader(readfile)
    total_pages = input_pdf.getNumPages()
    for page in range(total_pages - 1, -1, -1):
        output_pdf.addPage(input_pdf.getPage(page))
    with open(r'output.pdf', "wb") as writefile:
        output_pdf.write(writefile)

我还建议使用更符合Python风格的方法，直接用reversed来遍历页面：

from PyPDF2 import PdfFileWriter, PdfFileReader

output_pdf = PdfFileWriter()

with open('input.pdf', 'rb') as readfile:
    input_pdf = PdfFileReader(readfile)

    for page in reversed(input_pdf.pages):
        output_pdf.addPage(page)

    with open('output.pdf', "wb") as writefile:
        output_pdf.write(writefile)

我不知道这个.pages集合在原来的pyPdf中是否可用，但现在看来这并不太重要。

Answer 2

谢谢你们分享的建议。我根据这些建议做了一些修改，让选择和保存文件的界面看起来更直观一些。我对这些东西还很陌生，我添加的内容可能不是最有效或最简洁的，但对我来说是有效的，所以我想分享出来。

from PyPDF2 import PdfFileWriter, PdfFileReader
import tkinter as tk
from tkinter import filedialog
import ntpath
import os


output_pdf = PdfFileWriter()

# grab the location of the file path sent
def path_leaf(path):
    head, tail = ntpath.split(path)
    return head

# graphical file selection
def grab_file_path():
    # use dialog to select file
    file_dialog_window = tk.Tk()
    file_dialog_window.withdraw()  # hides the tk.TK() window
    # use dialog to select file
    grabbed_file_path = filedialog.askopenfilename()
    return grabbed_file_path


# file to be reversed
filePath = grab_file_path()

# open file and read
with open(filePath, 'rb') as readfile:
    input_pdf = PdfFileReader(readfile)

    # reverse order one page at time
    for page in reversed(input_pdf.pages):
        output_pdf.addPage(page)

    # graphical way to get where to select file starting at input file location
    dirOfFileToBeSaved = path_leaf(filePath)
    locationOfFileToBeSaved=filedialog.asksaveasfilename(initialdir=dirOfFileToBeSaved, initialfile='name of reversed file.pdf',title="Select or type file name and location", filetypes=[("pdf files", "*.pdf")])
    # write the file created
    with open(locationOfFileToBeSaved, "wb") as writefile:
        output_pdf.write(writefile)

# open the file when done
os.startfile(locationOfFileToBeSaved)

Answer 3

from pyPdf import PdfFileWriter, PdfFileReader
output_pdf = PdfFileWriter()

with open(r'input.pdf', 'rb') as readfile:
    input_pdf = PdfFileReader(readfile)
    total_pages = input_pdf.getNumPages()
    for page in xrange(total_pages - 1, -1, -1):
        output_pdf.addPage(input_pdf.getPage(page))
    with open(r'output.pdf', "wb") as writefile:
        output_pdf.write(writefile)

当然可以！请把你想要翻译的内容发给我，我会帮你用简单易懂的语言解释清楚。

如何使用pyPdf反转PDF文件中页面的顺序？

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