PDFMiner-遍历页面并将其转换为tex

Question

所以我试图从一些pdf中获取特定的文本，我在PDFMiner中使用Python，但是由于在November 2013中对它进行的API更改而遇到了一些问题。基本上，要从PDF中获取我想要的部分文本，我目前必须将整个文件转换为文本，然后使用字符串函数获取我想要的部分。我要做的是循环浏览PDF的每一页，并将每一页逐个转换为文本。一旦我找到了我想要的部分，我就停止阅读PDF。

我会把放在我的文本编辑器atm中的代码发出去，但它不是工作版本，而是高效解决方案版本的一半：p

#!/usr/bin/env python
# -*- coding: utf-8 -*- 

from pdfminer.pdfparser import PDFParser
from pdfminer.pdfdocument import PDFDocument
from pdfminer.pdfpage import PDFPage
from pdfminer.pdfinterp import PDFResourceManager
from pdfminer.pdfinterp import PDFPageInterpreter
from pdfminer.pdfdevice import PDFDevice
from pdfminer.converter import LTChar, TextConverter
from pdfminer.layout import LAParams
from subprocess import call
from cStringIO import StringIO
import re
import sys
import os

argNum = len(sys.argv)
pdfLoc = str(sys.argv[1]) #CLI arguments

def convert_pdf_to_txt(path): #converts pdf to raw text (not my function)
    rsrcmgr = PDFResourceManager()
    retstr = StringIO()
    codec = 'utf-8'
    laparams = LAParams()
    device = TextConverter(rsrcmgr, retstr, codec=codec, laparams=laparams)
    fp = file(path, 'rb')
    interpreter = PDFPageInterpreter(rsrcmgr, device)
    password = ""
    maxpages = 0
    caching = True
    pagenos=set()
    for page in PDFPage.get_pages(fp, pagenos, maxpages=maxpages, password=password,caching=caching, check_extractable=True):
        interpreter.process_page(page)

    fp.close()
    device.close()
    str = retstr.getvalue()
    retstr.close()
    return str

if (pdfLoc[-4:] == ".pdf"):
    contents = ""
    try: # Get the outlines (contents) of the document
        fp = open(pdfLoc, 'rb') #open a pdf document for reading
        parser = PDFParser(fp)
        document = PDFDocument(parser)
        outlines = document.get_outlines()
        for (level,title,dest,a,se) in outlines:
            title = re.sub(r".*\s", "", title) #get raw titles, stripped of formatting
            contents += title + "\n"
    except: #if pdfMiner can't get contents then manually get contents from text conversion
        #contents = convert_pdf_to_txt(pdfLoc)
        #startToCpos = contents.find("TABLE OF CONTENTS")
        #endToCpos = contents.rfind(". . .")
        #contents = contents[startToCpos:endToCpos+8]

        fp = open(pdfLoc, 'rb') #open a pdf document for reading
        parser = PDFParser(fp)
        document = PDFDocument(parser)
        pages = PDFPage(document, 3, {'Resources':'thing', 'MediaBox':'Thing'}) #God knows what's going on here
        for pageNumber, page in enumerate(pages.get_pages(PDFDocument, fp)): #The hell is the first argument?
            if pageNumber == 42:
                print "Hello"

        #for line in s:
        #   print line
        #   if (re.search("(\.\s){2,}", line) and not re.search("NOTES|SCOPE", line)):
        #       line = re.sub("(\.\s){2,}", "", line)
        #       line = re.sub("(\s?)*[0-9]*\n", "\n", line)
        #       line = re.sub("^\s", "", line)
        #       print line,


        #contents = contents.lower()
        #contents = re.sub("“", "\"", contents)
        #contents = re.sub("”", "\"", contents)
        #contents = re.sub("fi", "f", contents)
        #contents = re.sub(r"(TABLE OF CONTENTS|LIST OF TABLES|SCOPE|REFERENCED DOCUMENTS|Identification|System (o|O)verview|Document (o|O)verview|Title|Page|Table|Tab)(\n)?|\.\s?|Section|[0-9]", "", contents)
        #contents = re.sub(r"This document contains proprietary information and may not be reproduced in any form whatsoever, nor may be used by or its contents divulged to third\nparties without written permission from the ownerAll rights reservedNumber:  STP SMEDate: -Jul-Issue: A  of CMC STPNHIndustriesCLASSIFICATION\nNATO UNCLASSIFIED                  AGUSTAEUROCOPTEREUROCOPTER DEUTSCHLAND                 FOKKER", "", contents)
        #contents = re.sub(r"(\r?\n){2,}", "", contents)
        #contents = contents.lstrip()
        #contents = contents.rstrip()
    #print contents
else:
    print "Not a valid PDF file"

This is the old way of doing it（或者至少是一个旧方法的想法，线程对我来说不是很有用）。但现在我必须使用PDFPage.get_pages而不是PDFDocument.get_pages，方法和它们的参数完全不同。

目前，我正试图弄清楚究竟什么是'Klass'变量，我传递给了PDFPage的get-pages方法。

如果有人能对API的这一部分有所了解，甚至能提供一个实际的例子，我将非常感激。

Answer 1

尝试使用PyPDF2。它使用起来要简单得多，而且不像PDFMiner那样具有不必要的丰富功能（这对您的情况很好）。这是你想要的，实现起来非常简单。

from PyPDF2 import PdfFileReader

PDF = PdfFileReader(file(pdf_fp, 'rb'))

if PDF.isEncrypted:
    decrypt = PDF.decrypt('')
    if decrypt == 0:
        print "Password Protected PDF: " + pdf_fp
        raise Exception("Nope")
    elif decrypt == 1 or decrypt == 2:
        print "Successfully Decrypted PDF"

for page in PDF.pages:
    print page.extractText()
    '''page.extractText() is the unicode string of the contents of the page
    And I am assuming you know how to play with a string and use regex
    If you find what you want just break like so:
    if some_condition == True:
        break'''

Answer 2

也许我有点晚了，你已经解决了这个问题，但是，为了将来的参考：

经过大量的搜索，我想起了这个link，从中我将指出以下部分（粗体相关部分）：

Python decided to do methods in a way that makes the instance to which the method belongs be passed automatically, but not received automatically: the first parameter of methods is the instance the method is called on. That makes methods entirely the same as functions, and leaves the actual name to use up to you (although self is the convention, and people will generally frown at you when you use something else.) self is not special to the code, it's just another object.