How to extract text from a PDF? [closed]_问答_开发者

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Can anyone recommend a library/API for extracting the text and images from a PDF? We need to be able to get at text that is contained in pre-known regions of the document, so the API will need to give us positional information of each element on the page.

We would like that data to be output in xml or json format. We're currently looking at PdfTextStream which seems pretty good, but would like to hear other peoples experiences and suggestions.

Are there alternatives (commercial ones or 开发者_Python百科free) for extracting text from a pdf programatically?

I was given a 400 page pdf file with a table of data that I had to import - luckily no images. Ghostscript worked for me:

gswin64c -sDEVICE=txtwrite -o output.txt input.pdf

The output file was split into pages with headers, etc., but it was then easy to write an app to strip out blank lines, etc, and suck in all 30,000 records. -dSIMPLE and -dCOMPLEX made no difference in this case.

An efficient command line tool, open source, free of any fee, available on both linux & windows : simply named pdftotext. This tool is a part of the xpdf library.

http://en.wikipedia.org/wiki/Pdftotext

Since today I know it: the best thing for text extraction from PDFs is TET, the text extraction toolkit. TET is part of the PDFlib.com family of products.

PDFlib.com is Thomas Merz's company. In case you don't recognize his name: Thomas Merz is the author of the "PostScript and PDF Bible".

TET's first incarnation is a library. That one can probably do everything Budda006 wanted, including positional information about every element on the page. Oh, and it can also extract images. It recombines images which are fragmented into pieces.

pdflib.com also offers another incarnation of this technology, the TET plugin for Acrobat. And the third incarnation is the PDFlib TET iFilter. This is a standalone tool for user desktops. Both these are free (as in beer) to use for private, non-commercial purposes.

And it's really powerful. Way better than Adobe's own text extraction. It extracted text for me where other tools (including Adobe's) do spit out garbage only.

I just tested the desktop standalone tool, and what they say on their webpage is true. It has a very good commandline. Some of my "problematic" PDF test files the tool handled to my full satisfaction.

This thing will from now on be my recommendation for every sophisticated and challenging PDF text extraction requirements.

TET is simply awesome. It detects tables. Inside tables, it identifies cells spanning multiple columns. It identifies table rows and contents of each table cell separately. It deals very well with hyphenations: it removes hyphens and restores complete words. It supports non-ASCII languages (including CJK, Arabic and Hebrew). When encountering ligatures, it restores the original characters...

Give it a try.

For python, there is PDFMiner and pyPDF2. For more information on these, see Python module for converting PDF to text.

Here is my suggestion. If you want to extract text from PDF, you could import the pdf file into Google Docs, then export it to a more friendly format such as .html, .odf, .rtf, .txt, etc. All of this using the Drive API. It is free* and robust. Take a look at:

https://developers.google.com/drive/v2/reference/files/insert https://developers.google.com/drive/v2/reference/files/get

Because it is a rest API, it is compatible with ALL programing languages. The links I posted aboove have working examples for many languages including: Java, .NET, Python, PHP, Ruby, and others.

I hope it helps.

PdfTextStream (which you said you have been looking at) is now free for single threaded applications. In my opinion its quality is much better than other libraries (esp. for things like funky embedded fonts, etc).

It is available in Java and C#.

Alternatively, you should have a look at Apache PDFBox, open source.

One of the comments here used gs on Windows. I had some success with that on Linux/OSX too, with the following syntax:

gs \
 -q \
 -dNODISPLAY \
 -dSAFER \
 -dDELAYBIND \
 -dWRITESYSTEMDICT \
 -dSIMPLE \
 -f ps2ascii.ps \
 "${input}" \
 -dQUIET \
 -c quit

I used dSIMPLE instead of dCOMPLEX because the latter outputs 1 character per line.

Docotic.Pdf library may be used to extract text from PDF files as plain text or as a collection of text chunks with coordinates for each chunk.

Docotic.Pdf can be used to extract images from PDFs, too.

Disclaimer: I work for Bit Miracle.

As the question is specifically about alternative tools to get data from PDF as XML so you may be interested to take a look at the commercial tool "ByteScout PDF Extractor SDK" that is capable of doing exactly this: extract text from PDF as XML along with the positioning data (x,y) and font information:

Text in the source PDF:

Products | Units | Price

Output XML:

 <row>
 <column>
  <text fontName="Arial" fontSize="11.0" fontStyle="Bold" x="212" y="126" width="47" height="11">Products</text> 
  </column>
 <column>
  <text fontName="Arial" fontSize="11.0" fontStyle="Bold" x="428" y="126" width="27" height="11">Units</text> 
  </column>
 <column>
  <text fontName="Arial" fontSize="11.0" fontStyle="Bold" x="503" y="126" width="26" height="11">Price</text> 
  </column>
</row>

P.S.: additionally it also breaks the text into a table based structure.

Disclosure: I work for ByteScout

The best thing I can currently think of (within the list of "simple" tools) is Ghostscript (current version is v.8.71) and the PostScript utility program ps2ascii.ps. Ghostscript ships it in its lib subdirectory. Try this (on Windows):

gswin32c.exe ^
   -q ^
   -sFONTPATH=c:/windows/fonts ^
   -dNODISPLAY ^
   -dSAFER ^
   -dDELAYBIND ^
   -dWRITESYSTEMDICT ^
   -dCOMPLEX ^
   -f ps2ascii.ps ^
   -dFirstPage=3 ^
   -dLastPage=7 ^
   input.pdf ^
   -dQUIET ^
   -c quit

This command processes pages 3-7 of input.pdf. Read the comments in the ps2ascii.ps file itself to see what the "weird" numbers and additional infos mean (they indicate strings, positions, widths, colors, pictures, rectangles, fonts and page breaks...). To get a "simple" text output, replace the -dCOMPLEX part by -dSIMPLE.

I know that this topic is quite old, but this need is still alive. I read many documents, forum and script and build a new advanced one which supports compressed and uncompressed pdf :

https://gist.github.com/smalot/6183152

In some cases, command line is forbidden for security reasons. So a native PHP class can fit many needs.

Hope it helps everone

For image extraction, pdfimages is a free command line tool for Linux or Windows (win32):

pdfimages: Extract and Save Images From A Portable Document Format ( PDF ) File

Apache pdfbox has this feature - the text part is described in:

http://pdfbox.apache.org/apidocs/org/apache/pdfbox/util/PDFTextStripper.html

for an example implementation see https://github.com/WolfgangFahl/pdfindexer

the testcase TestPdfIndexer.testExtracting shows how it works

QuickPDF seems to be a reasonable library that should do what you want for a reasonable price.

http://www.quickpdflibrary.com/ - They have a 30 day trial.

On my Macintosh systems, I find that "Adobe Reader" does a reasonably good job. I created an alias on my Desktop that points to the "Adobe Reader.app", and all I do is drop a pdf-file on the alias, which makes it the active document in Adobe Reader, and then from the File-menu, I choose "Save as Text...", give it a name and where to save it, click "Save", and I'm done.