Python to read PDF files [duplicate] - python

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How to extract text from a PDF file?
(33 answers)
Closed 1 year ago.
I have found many posts where solutions to read PDFs has been proposed. I want to read a PDF file word by word and do some processing on it. people suggest pdfMiner which converts entire PDF file into text file. But what i want is that to read PDFs word by word. Can anyone suggest a library that does this?

Possibly the fastest way to do this is to first convert your pdf inta a text file using pdftotext (on pdfMiner's site, there's a statement that pdfMiner is 20 times slower than pdftotext) and afterwards parse the text file as usual.
Also, when you said "I want to read a pdf file word by word and do some processing on it", you didn't specify if you want to do processing based on words in a pdf file, or do you actually want to modify the pdf file itself. If it's the second case, then you've got an entirely different problem on your hands.

I'm using pdfminer and it is an excellent lib especially if you're comfortable programming in python. It reads PDF and extracts every character, and it provides its bounding box as a tuple (x0,y0,x1,y1). Pdfminer will extract rectangles, lines and some images, and will try to detect words. It has an unpleasant O(N^3) routine that analyses bounding boxes to coalesce them, so it can get very slow on some files. Try to convert your typical file - maybe it'll be fast for you, or maybe it'll take 1 hour, depends on the file.
You can easily dump a pdf out as text, that's the first thing you should try for your application. You can also dump XML (see below), but you can't modify PDF. XML is the most complete representation of the PDF you can get out of it.
You have to read through the examples to use it in your python code, it doesn't have much documentation.
The example that comes with PdfMiner that transforms PDF into xml shows best how to use the lib in your code. It also shows you what's extracted in human-readable (as far as xml goes) form.
You can call it with parameters that tell it to "analyze" the pdf. If you do, it'll coalesce letters into blocks of text (words and sentences; sentences will have spaces so it's easy to tokenize into words in python).

Whereas I really liked the pdfminer answer I'd say that packages are not the same over time. Currenlty pdfminer still not support Python3 and may need to be updated.
So, to update the subject -even if an answer have been already voted- I'd propose to go pdfrw, from the website :
Version 0.3 is tested and works on Python 2.6, 2.7, 3.3, 3.4, and 3.5
Operations include subsetting, merging, rotating, modifying metadata,etc
The fastest pure Python PDF parser available Has been used for years by a printer in pre-press production
Can be used with rst2pdf to faithfully reproduce vector images
Can be used either standalone, or in conjunction with reportlab to reuse existing PDFs in new ones
Permissively licensed

Related

How to convert pdf to xml /json using python code

Can any one help me on how to convert pdf file to xml file using python code? My pdf contains:
Unstructured data
It has images
Mathematical equations
Chemical Equations
Table Data
Logo's tag's etc.
I tried using PDFMiner, but my pdf data was not converted into .xml/json file format. Are there any libraries other than PDFMiner? PyPDF2, Tabula-py, PDFQuery, comelot, PyMuPDF, pdf to dox, pandas- these other libraries/utilities all not suitable for my requirement.
Please advise me on any other options. Thank you.
The first thing I would recommend you trying is GROBID (see here for the full documentation). You can play with an online demo here to see if fits your needs (select TEI -> Process Fulltext Document, and upload a PDF). You can also check out this from the Allen Institute (it is based on GROBID and has a handy function for converting TEI.XML to JSON).
The other package which--obviously--does a good job is the Adobe PDF Extract API (see here). It's of course a paid service but when you register for an account you get 1.000 document transactions for free. It's easy to implement in Python, well documented, and a good way for experimenting and getting a feel for the difficulties of reliable data extraction from PDF.
I worked with both options to extract text, figures, tables etc. from scientific papers. Both yielded good results. The main problem with out-of-the-box solutions is that, when you work with complex formats (or badly formatted docs), erroneously identified document elements are quite common (for example a footnote or a header gets merged with the main text). Both options are based on machine learning models and, at least for GROBID, it is possible to retrain these models for your specific task (I haven't tried this so far, so I don't know how worthwhile it is).
However, if your target PDFs are all of the same (simple) format (or if you can control their format) you should be fine with either option.

Can't get text out of PDF file with PyPDF2

I am trying to get the text from a PDF file I downloaded with PyPDF.
Here is my code:
if not PyPDF2.PdfFileReader('download.pdf').isEncrypted:
PyPDF2.PdfFileReader('download.pdf').getPage(0).extractText()
This is the output:
'\n\n˘ˇ˘ˆ˙\n˝˛˚˜!\n\n\n\n#\nˇ˘ˆ˙ˆ˝˛˝\n˙˙˘ ˘ˆ"˝\n$!%˙(˝)˙*˜+,˝-.#/.(#0)0)/.1.+02345.\n˛˛ˇ/#.$/0/70/#.+322.32˙˘˛˘˘\n˛˘ 8˙˘9:˘ˆ;\n˛˘\n\n˝=\n˙˘˛\n.ˇ<9:˘ˇˇ%˘˛ˇ ˘˘<˘\n˝>"?˝˘$#<˘*ˆˆ˘˙˘A˘B˘˙˘˛ˇ!˛˘˙˘˛ˇ˘\n1C˙ˆ˘06˛˘8+˛9:˘D10+E˝ˆ˘8\n$˘˘9:˘˘1C˙ˆ˘+˘F˛˘D$1+FE˝˘˛˘˘<˘?˝\n////)*˘1˘˛ ?GG˜*HI\nD˘˙A˘E\nJ$\n˛\nDLE///M˛˝˛˙˘˛˘˛\n˛˘˛>"?\n˙˘˛\n˛\n/)M6;˝˛˙˘˛˘\n˛\n///˛\n\n'
When I open the file its content is fine. Also when I use another program to transform pdf into txt it works fine. It is a javascript rendered pdf on a webpage, don't know if it makes any difference.
Under Win 7, Python 3.6, I had the problem that PyPDF2 did not properly encode some PDF files. My solution was to use pdfminer.six.
pip install pdfminer.six
To extract text from a PDF, you can use functions such as the one in this post: https://stackoverflow.com/a/42154976/9524424
Worked perfect for me...
The following is taken from the documentation (https://pythonhosted.org/PyPDF2/PageObject.html)
extractText() Locate all text drawing commands, in the order they are
provided in the content stream, and extract the text. This works well
for some PDF files, but poorly for others, depending on the generator
used. This will be refined in the future. Do not rely on the order of
text coming out of this function, as it will change if this function
is made more sophisticated. Returns: a unicode string object.
So, it seems that the performance of this function depends on the pdf itself.

Python PDF text extraction - Unable to extract from a specific document with pdfminer/textract

I am using Python to do a project which involves extracting text from many PDF documents, interestingly I've come across a document which is unable to be parsed by either of these projects:
https://github.com/euske/pdfminer/
https://github.com/deanmalmgren/textract
Indeed, even the command line tool pdftotext cannot extract the text from the document. It prints text at first, then proceeds to print garbage after about 2 minutes of extraction.
The document can be found here: https://www.aiaa.org/uploadedFiles/Events/Conferences/2013_Conferences/2013_-_GNC_Infotech/Promotional_Materials/GNC%202013%20Final%20Program.pdf
I'm interested in one of two solutions:
How could I accomplish the goal of extracting the text from this document in Python?
How could I detect documents like this in general, so I could avoid trying to parse them altogether?
Either of these solutions would be ideal, so thanks in advance!
I use Jupyter with Python 3.6 under win10. In this case I have to use pdfminer.six.
I had to re-install all in these days. This does still work for me

Can you modify only a text string in an XML file and still maintain integrity and functionality of .docx encasement?

I want to enter data into a Microsoft Excel Spreadsheet, and for that data to interact and write itself to other documents and webforms.
With success, I am pulling data from an Excel spreadsheet using xlwings. Right now, I’m stuck working with .docx files. The goal here is to write the Excel data into specific parts of a Microsoft Word .docx file template and create a new file.
My specific question is:
Can you modify just a text string(s) in a word/document.xml file and still maintain the integrity and functionality of its .docx encasement? It seems that there are numerous things that can change in the XML code when making even the slightest change to a Word document. I've been working with python-docx and lxml, but I'm not sure if what I seek to do is possible via this route.
Any suggestions or experiences to share would be greatly appreciated. I feel I've read every article that is easily discoverable through a google search at least 5 times.
Let me know if anything needs clarification.
Some things to note:
I started getting into coding about 2 months ago. I’ve been doing it intensively for that time and I feel I’m picking up the essential concepts, but there are severe gaps in my knowledge.
Here are my tools:
Yosemite 10.10,
Microsoft Office 2011 for Mac
You probably need to be more specific, but the short answer is, in principle, yes.
At a certain level, all python-docx does is modify strings in the XML. A couple things though:
The XML you create needs to remain well-formed and valid according to the schema. So if you change the text enclosed in a <w:t> element, for example, that works fine. Conversely, if you inject a bunch of random XML at an arbitrary point in one of the .xml parts, that will corrupt the file.
The XML "files", known as parts that make up a .docx file are contained in a Zip archive known as a package. You must unpackage and repackage that set of parts properly in order to have a valid .docx file afterward. python-docx takes care of all those details for you, but if you're going directly at the .docx file you'll need to take care of that yourself.

How to parse just the text from a Word Doc using Python?

When you try opening a MS Word document or for that matter most Windows file formats, you will see gibberish as given below broken intermittently by the actual text. I need to extract the text that goes in and want to ignore the gibberish -- which is something like given below. How do I extract only the text that matters, and ignore rest of the stuff. Please advise.
Here's a sample of open("sample.doc",r").read() of a word doc. Thanks
00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00In an Interesting news,his is the first time we polled Indian channel community for their preferred memory supplier. Transcend came a close second, was seen to be more popular among class A city based resellers, was also the most recalled memory brand among customers according to resellers. However Transcend channels complained of parallel imports and constant unavailability of the products in grey x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x
The tool that seems the most viable, particularly if you need an all python solution is OleFileIO.
doc is a binary format, it's not a markup language or something.
Specs: http://www.microsoft.com/interop/docs/OfficeBinaryFormats.mspx
There is no generic why to extract
information from every file format.
You need to know the format to know
how to extract the information.
Just wanted to state that first. So what you should look for is libraries and software that can convert/extract the information you want. And as mentioned by Ofir MicroSoft have tools for that for their formats.
But if you can not do this and want to take the chance that there is text visible in the file that you think is interesting to read you could do a normal read and look for sequences of bytes that will build text. Then comes the question, what languages/charset should I support support in my hunt for text. Is it multi-byte text?
The easy start is to loop through the data and look for sequences of [a-zA-z0-9_- ] to find the text. But word is probably multi-byte. So you should scan double byte as one char.
Note: some of the new formats like open office and docx is multiple files in a compressed container. So you need to de-compress the file first, and scan XML documents after the text you looking for.
Word doc is a compressed format. You need to uncompress it first to get the real data (try open a doc file in a program like winrar, and you'll see it contains multiple files.
It even seems to be XML, so reading the format should not be that hard, although I'm not sure if you get all the data this way.
I had a similar problem, needing to query hundreds of Word documents. I converted the Word files to text files and used normal text parsing tools. Worked well.

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