如何“写入变量"?而不是“归档"在Python中 [英] How to "write to variable" instead of "to file" in Python

问题描述

我正在尝试编写一个将pdf拆分为单独页面的函数.来自此SO答案.我复制了一个简单的函数，该函数将pdf拆分为单独的页面:

I'm trying to write a function which splits a pdf into separate pages. From this SO answer. I copied a simple function which splits a pdf into separate pages:

def splitPdf(file_):
    pdf = PdfFileReader(file_)
    pages = []
    for i in range(pdf.getNumPages()):
        output = PdfFileWriter()
        output.addPage(pdf.getPage(i))
        with open("document-page%s.pdf" % i, "wb") as outputStream:
            output.write(outputStream)
    return pages

但是，这会将新的PDF写入文件，而不是将新PDF的列表作为文件变量返回.所以我将output.write(outputStream)的行更改为:

This however, writes the new PDFs to file, instead of returning a list of the new PDFs as file variables. So I changed the line of output.write(outputStream) to:

pages.append(outputStream)

但是，当尝试在页面列表中写入元素时，我得到了ValueError: I/O operation on closed file.

When trying to write the elements in the pages list however, I get a ValueError: I/O operation on closed file.

有人知道如何将新文件添加到列表中并返回它们，而不是将它们写入文件吗?欢迎所有提示！

Does anybody know how I can add the new files to the list and return them, instead of writing them to file? All tips are welcome!

推荐答案

作为文件变量的PDF列表"的含义还不是很清楚.如果要创建字符串而不是文件PDF内容，并返回此类字符串的列表，将open()替换为StringIO并调用getvalue()以获得内容:

It is not completely clear what you mean by "list of PDFs as file variables. If you want to create strings instead of files with PDF contents, and return a list of such strings, replace open() with StringIO and call getvalue() to obtain the contents:

import cStringIO

def splitPdf(file_):
    pdf = PdfFileReader(file_)
    pages = []
    for i in range(pdf.getNumPages()):
        output = PdfFileWriter()
        output.addPage(pdf.getPage(i))
        io = cStringIO.StringIO()
        output.write(io)
        pages.append(io.getvalue())
    return pages

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