Python module for converting PDF to text [closed]

Answer 1

You can also quite easily use pdfminer as a library. You have access to the pdf's content model, and can create your own text extraction. I did this to convert pdf contents to semi-colon separated text, using the code below.

The function simply sorts the TextItem content objects according to their y and x coordinates, and outputs items with the same y coordinate as one text line, separating the objects on the same line with ';' characters.

Using this approach, I was able to extract text from a pdf that no other tool was able to extract content suitable for further parsing from. Other tools I tried include pdftotext, ps2ascii and the online tool pdftextonline.com.

pdfminer is an invaluable tool for pdf-scraping.

def pdf_to_csv(filename):
    from pdflib.page import TextItem, TextConverter
    from pdflib.pdfparser import PDFDocument, PDFParser
    from pdflib.pdfinterp import PDFResourceManager, PDFPageInterpreter

    class CsvConverter(TextConverter):
        def __init__(self, *args, **kwargs):
            TextConverter.__init__(self, *args, **kwargs)

        def end_page(self, i):
            from collections import defaultdict
            lines = defaultdict(lambda : {})
            for child in self.cur_item.objs:
                if isinstance(child, TextItem):
                    (_,_,x,y) = child.bbox
                    line = lines[int(-y)]
                    line[x] = child.text

            for y in sorted(lines.keys()):
                line = lines[y]
                self.outfp.write(";".join(line[x] for x in sorted(line.keys())))
                self.outfp.write("\n")

    # ... the following part of the code is a remix of the 
    # convert() function in the pdfminer/tools/pdf2text module
    rsrc = PDFResourceManager()
    outfp = StringIO()
    device = CsvConverter(rsrc, outfp, "ascii")

    doc = PDFDocument()
    fp = open(filename, 'rb')
    parser = PDFParser(doc, fp)
    doc.initialize('')

    interpreter = PDFPageInterpreter(rsrc, device)

    for i, page in enumerate(doc.get_pages()):
        outfp.write("START PAGE %d\n" % i)
        interpreter.process_page(page)
        outfp.write("END PAGE %d\n" % i)

    device.close()
    fp.close()

    return outfp.getvalue()

UPDATE:

The code above is written against an old version of the API, see my comment below.

Answer 2

I have used pdftohtml with the -xml argument, read the result with subprocess.Popen(), that will give you x coord, y coord, width, height, and font, of every snippet of text in the pdf. I think this is what 'evince' probably uses too because the same error messages spew out.

If you need to process columnar data, it gets slightly more complicated as you have to invent an algorithm that suits your pdf file. The problem is that the programs that make PDF files don't really necessarily lay out the text in any logical format. You can try simple sorting algorithms and it works sometimes, but there can be little 'stragglers' and 'strays', pieces of text that don't get put in the order you thought they would. So you have to get creative.

It took me about 5 hours to figure out one for the pdf's I was working on. But it works pretty good now. Good luck.

Answer 3

Additionally there is PDFTextStream which is a commercial Java library that can also be used from Python.

Answer 4

I needed to convert a specific PDF to plain text within a python module. I used PDFMiner 20110515, after reading through their pdf2txt.py tool I wrote this simple snippet:

from cStringIO import StringIO
from pdfminer.pdfinterp import PDFResourceManager, process_pdf
from pdfminer.converter import TextConverter
from pdfminer.layout import LAParams

def to_txt(pdf_path):
    input_ = file(pdf_path, 'rb')
    output = StringIO()

    manager = PDFResourceManager()
    converter = TextConverter(manager, output, laparams=LAParams())
    process_pdf(manager, converter, input_)

    return output.getvalue() 

Answer 5

Pdftotext An open source program (part of Xpdf) which you could call from python (not what you asked for but might be useful). I've used it with no problems. I think google use it in google desktop.

Answer 6

The PDFMiner package has changed since codeape posted.

EDIT (again):

PDFMiner has been updated again in version 20100213

You can check the version you have installed with the following:

>>> import pdfminer
>>> pdfminer.__version__
'20100213'

Here's the updated version (with comments on what I changed/added):

def pdf_to_csv(filename):
    from cStringIO import StringIO  #<-- added so you can copy/paste this to try it
    from pdfminer.converter import LTTextItem, TextConverter
    from pdfminer.pdfparser import PDFDocument, PDFParser
    from pdfminer.pdfinterp import PDFResourceManager, PDFPageInterpreter

    class CsvConverter(TextConverter):
        def __init__(self, *args, **kwargs):
            TextConverter.__init__(self, *args, **kwargs)

        def end_page(self, i):
            from collections import defaultdict
            lines = defaultdict(lambda : {})
            for child in self.cur_item.objs:
                if isinstance(child, LTTextItem):
                    (_,_,x,y) = child.bbox                   #<-- changed
                    line = lines[int(-y)]
                    line[x] = child.text.encode(self.codec)  #<-- changed

            for y in sorted(lines.keys()):
                line = lines[y]
                self.outfp.write(";".join(line[x] for x in sorted(line.keys())))
                self.outfp.write("\n")

    # ... the following part of the code is a remix of the 
    # convert() function in the pdfminer/tools/pdf2text module
    rsrc = PDFResourceManager()
    outfp = StringIO()
    device = CsvConverter(rsrc, outfp, codec="utf-8")  #<-- changed 
        # becuase my test documents are utf-8 (note: utf-8 is the default codec)

    doc = PDFDocument()
    fp = open(filename, 'rb')
    parser = PDFParser(fp)       #<-- changed
    parser.set_document(doc)     #<-- added
    doc.set_parser(parser)       #<-- added
    doc.initialize('')

    interpreter = PDFPageInterpreter(rsrc, device)

    for i, page in enumerate(doc.get_pages()):
        outfp.write("START PAGE %d\n" % i)
        interpreter.process_page(page)
        outfp.write("END PAGE %d\n" % i)

    device.close()
    fp.close()

    return outfp.getvalue()

Edit (yet again):

Here is an update for the latest version in pypi, 20100619p1. In short I replaced LTTextItem with LTChar and passed an instance of LAParams to the CsvConverter constructor.

def pdf_to_csv(filename):
    from cStringIO import StringIO  
    from pdfminer.converter import LTChar, TextConverter    #<-- changed
    from pdfminer.layout import LAParams
    from pdfminer.pdfparser import PDFDocument, PDFParser
    from pdfminer.pdfinterp import PDFResourceManager, PDFPageInterpreter

    class CsvConverter(TextConverter):
        def __init__(self, *args, **kwargs):
            TextConverter.__init__(self, *args, **kwargs)

        def end_page(self, i):
            from collections import defaultdict
            lines = defaultdict(lambda : {})
            for child in self.cur_item.objs:
                if isinstance(child, LTChar):               #<-- changed
                    (_,_,x,y) = child.bbox                   
                    line = lines[int(-y)]
                    line[x] = child.text.encode(self.codec)

            for y in sorted(lines.keys()):
                line = lines[y]
                self.outfp.write(";".join(line[x] for x in sorted(line.keys())))
                self.outfp.write("\n")

    # ... the following part of the code is a remix of the 
    # convert() function in the pdfminer/tools/pdf2text module
    rsrc = PDFResourceManager()
    outfp = StringIO()
    device = CsvConverter(rsrc, outfp, codec="utf-8", laparams=LAParams())  #<-- changed
        # becuase my test documents are utf-8 (note: utf-8 is the default codec)

    doc = PDFDocument()
    fp = open(filename, 'rb')
    parser = PDFParser(fp)       
    parser.set_document(doc)     
    doc.set_parser(parser)       
    doc.initialize('')

    interpreter = PDFPageInterpreter(rsrc, device)

    for i, page in enumerate(doc.get_pages()):
        outfp.write("START PAGE %d\n" % i)
        if page is not None:
            interpreter.process_page(page)
        outfp.write("END PAGE %d\n" % i)

    device.close()
    fp.close()

    return outfp.getvalue()

EDIT (one more time):

Updated for version 20110515 (thanks to Oeufcoque Penteano!):

def pdf_to_csv(filename):
    from cStringIO import StringIO  
    from pdfminer.converter import LTChar, TextConverter
    from pdfminer.layout import LAParams
    from pdfminer.pdfparser import PDFDocument, PDFParser
    from pdfminer.pdfinterp import PDFResourceManager, PDFPageInterpreter

    class CsvConverter(TextConverter):
        def __init__(self, *args, **kwargs):
            TextConverter.__init__(self, *args, **kwargs)

        def end_page(self, i):
            from collections import defaultdict
            lines = defaultdict(lambda : {})
            for child in self.cur_item._objs:                #<-- changed
                if isinstance(child, LTChar):
                    (_,_,x,y) = child.bbox                   
                    line = lines[int(-y)]
                    line[x] = child._text.encode(self.codec) #<-- changed

            for y in sorted(lines.keys()):
                line = lines[y]
                self.outfp.write(";".join(line[x] for x in sorted(line.keys())))
                self.outfp.write("\n")

    # ... the following part of the code is a remix of the 
    # convert() function in the pdfminer/tools/pdf2text module
    rsrc = PDFResourceManager()
    outfp = StringIO()
    device = CsvConverter(rsrc, outfp, codec="utf-8", laparams=LAParams())
        # becuase my test documents are utf-8 (note: utf-8 is the default codec)

    doc = PDFDocument()
    fp = open(filename, 'rb')
    parser = PDFParser(fp)       
    parser.set_document(doc)     
    doc.set_parser(parser)       
    doc.initialize('')

    interpreter = PDFPageInterpreter(rsrc, device)

    for i, page in enumerate(doc.get_pages()):
        outfp.write("START PAGE %d\n" % i)
        if page is not None:
            interpreter.process_page(page)
        outfp.write("END PAGE %d\n" % i)

    device.close()
    fp.close()

    return outfp.getvalue()