Extracting PDF Metadata and Text With Python
In this post, we take a look at how to use Python and some cool Python packages to extract a few different types of data from PDFs. Read on to get started!
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Join For FreeThere are lots of PDF-related packages for Python. One of my favorites is PyPDF2. You can use it to extract metadata, rotate pages, split or merge PDFs, and more. It's kind of a Swiss-army knife for existing PDFs. In this article, we will learn how to extract basic information about a PDF using PyPDF2.
Getting Started
PyPDF2 doesn't come as a part of the Python Standard Library, so you will need to install it yourself. The preferred way to do so is to use pip.
pip install pypdf2
Now that we have PyPDF2 installed, let's learn how to get metadata from a PDF!
Extracting Metadata
You can use PyPDF2 to extract a fair amount of useful data from any PDF. For example, you can learn the author of the document, its title and subject, and how many pages there are. Let's find out how by downloading the sample of this book from Leanpub at https://leanpub.com/reportlab. The sample I downloaded was called "reportlab-sample.pdf".
Here's the code:
# get_doc_info.py
from PyPDF2 import PdfFileReader
def get_info(path):
with open(path, 'rb') as f:
pdf = PdfFileReader(f)
info = pdf.getDocumentInfo()
number_of_pages = pdf.getNumPages()
print(info)
author = info.author
creator = info.creator
producer = info.producer
subject = info.subject
title = info.title
if __name__ == '__main__':
path = 'reportlab-sample.pdf'
get_info(path)
Here we import the PdfFileReader
class from PyPDF2
. This class gives us the ability to read a PDF and extract data from it using various accessor methods. The first thing we do is create our own get_info
function that accepts a PDF file path as its only argument. Then we open the file in read-only binary mode. Next, we pass that file handler into PdfFileReader
and create an instance of it.
Now we can extract some information from the PDF by using the getDocumentInfo
method. This will return an instance of PyPDF2.pdf.DocumentInformation
, which has the following useful attributes, among others:
- author
- creator
- producer
- subject
- title
If you print out the DocumentInformation
object, this is what you will see:
{ '/Author': 'Michael Driscoll',
'/CreationDate': "D:20180331023901-00'00'",
'/Creator': 'LaTeX with hyperref package',
'/Producer': 'XeTeX 0.99998',
'/Title': 'ReportLab - PDF Processing with Python' }
We can also get the number of pages in the PDF by calling the getNumPages
method.
Extracting Text From PDFs
PyPDF2 has limited support for extracting text from PDFs. It doesn't have built-in support for extracting images, unfortunately. I have seen some recipes on Stack Overflow that use PyPDF2 to extract images, but the code examples seem to be pretty hit or miss.
Let's try to extract the text from the first page of the PDF that we downloaded in the previous section:
# extracting_text.py
from PyPDF2 import PdfFileReader
def text_extractor(path):
with open(path, 'rb') as f:
pdf = PdfFileReader(f)
# get the first page
page = pdf.getPage(1)
print(page)
print('Page type: {}'.format(str(type(page))))
text = page.extractText()
print(text)
if __name__ == '__main__':
path = 'reportlab-sample.pdf'
text_extractor(path)
You will note that this code starts out in much the same way as our previous example. We still need to create an instance of PdfFileReader
. But, this time, we grab a page using the getPage
method. PyPDF2 is zero-based, much like most things in Python, so when you pass it a one, it actually grabs the second page. The first page, in this case, is just an image, so it wouldn't have any text.
Interestingly, if you run this example you will find that it doesn't return any text. Instead, all I got was a series of line break characters. Unfortunately, PyPDF2 has pretty limited support for extracting text. Even if it is able to extract text, it may not be in the order you expect and the spacing may be different as well.
To get this example code to work, you will need to try running it against a different PDF. I found one on the United States Internal Revenue Service website here: https://www.irs.gov/pub/irs-pdf/fw9.pdf
This is a W9 form for people who are self-employed or contract employees. It can be used in other situations too. Anyway, I downloaded it as w9.pdf and added it to the GitHub repository as well. If you use that PDF instead of the sample one, it will happily extract some of the text from page 2. I won't reproduce the output here as it is kind of lengthy though.
You may find that the pdfminer package works better for extracting text than PyPDF2 though.
Wrapping Up
The PyPDF2 package is quite useful. We were able to get some helpful information from PDFs using it. I could see using PyPDF on a folder of PDFs and using the metadata extraction technique to sort out the PDFs by creator name, subject, etc. Give it a try and see what you think!
Published at DZone with permission of Mike Driscoll, DZone MVB. See the original article here.
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