Working with PDF files in Python
All of you must be familiar with what PDFs are. In fact, they are one of the most important and widely used digital media. PDF stands for Portable Document Format. It uses .pdf extension. It is used to present and exchange documents reliably, independent of software, hardware, or operating system.
Invented by Adobe, PDF is now an open standard maintained by the International Organization for Standardization (ISO). PDFs can contain links and buttons, form fields, audio, video, and business logic.
In this article, we will learn, how we can do various operations like:
- Extracting text from PDF
- Rotating PDF pages
- Merging PDFs
- Splitting PDF
- Adding watermark to PDF pages
Installation:Using simple python scripts!
We will be using a third-party module, PyPDF2.
PyPDF2 is a python library built as a PDF toolkit. It is capable of:
- Extracting document information (title, author, …)
- Splitting documents page by page
- Merging documents page by page
- Cropping pages
- Merging multiple pages into a single page
- Encrypting and decrypting PDF files
- and more!
To install PyPDF2, run the following command from the command line:
pip3 install PyPDF2
This module name is case-sensitive, so make sure the y is lowercase and everything else is uppercase. All the code and PDF files used in this tutorial/article are available here.
1. Extracting text from PDF file
The output of the above program looks like this:
20 PythonBasics S.R.Doty August27,2008 Contents 1Preliminaries 4 1.1WhatisPython?................................... ..4 1.2Installationanddocumentation.................... .........4 [and some more lines...]
Let us try to understand the above code in chunks:
pdfFileObj = open('example.pdf', 'rb')
- We opened the example.pdf in binary mode.And saved the file object as pdfFileObj.
pdfReader = PyPDF2.PdfFileReader(pdfFileObj)
- Here, we create an object of PdfFileReader class of PyPDF2 module and pass the PDF file object & get a PDF reader object.
- numPages property gives the number of pages in the PDF file. For example, in our case, it is 20 (see first line of output).
pageObj = pdfReader.getPage(0)
- Now, we create an object of PageObject class of PyPDF2 module. PDF reader object has function getPage() which takes page number (starting from index 0) as argument and returns the page object.
- Page object has function extractText() to extract text from the PDF page.
- At last, we close the PDF file object.
Note: While PDF files are great for laying out text in a way that’s easy for people to print and read, they’re not straightforward for software to parse into plaintext. As such, PyPDF2 might make mistakes when extracting text from a PDF and may even be unable to open some PDFs at all. It isn’t much you can do about this, unfortunately. PyPDF2 may simply be unable to work with some of your particular PDF files.
2. Rotating PDF pages
Here, you can see how the first page of rotated_example.pdf looks like ( right image) after rotation:
There is a tool called UPDF that can be used to Rotate a PDF.
Some important points related to the above code:
- For rotation, we first create a PDF reader object of the original PDF.
pdfWriter = PyPDF2.PdfFileWriter()
- Rotated pages will be written to a new PDF. For writing to PDFs, we use the object of PdfFileWriter class of PyPDF2 module.
for page in range(pdfReader.numPages): pageObj = pdfReader.getPage(page) pageObj.rotateClockwise(rotation) pdfWriter.addPage(pageObj)
- Now, we iterate each page of the original PDF. We get page object by getPage() method of PDF reader class. Now, we rotate the page by rotateClockwise() method of page object class. Then, we add a page to PDF writer object using addPage() method of PDF writer class by passing the rotated page object.
newFile = open(newFileName, 'wb') pdfWriter.write(newFile) pdfFileObj.close() newFile.close()
- Now, we have to write the PDF pages to a new PDF file. Firstly, we open the new file object and write PDF pages to it using write() method of PDF writer object. Finally, we close the original PDF file object and the new file object.
3. Merging PDF files
The output of the above program is a combined PDF, combined_example.pdf, obtained by merging example.pdf and rotated_example.pdf.
- Let us have a look at important aspects of this program:
pdfMerger = PyPDF2.PdfFileMerger()
- For merging, we use a pre-built class, PdfFileMerger of PyPDF2 module.
Here, we create an object pdfMerger of PDF merger class
for pdf in pdfs: pdfmerger.append(open(focus, "rb"))
- Now, we append file object of each PDF to PDF merger object using the append() method.
with open(output, 'wb') as f: pdfMerger.write(f)
- Finally, we write the PDF pages to the output PDF file using write method of PDF merger object.
4. Splitting PDF file
Output will be three new PDF files with split 1 (page 0,1), split 2(page 2,3), split 3(page 4-end).
No new function or class has been used in the above python program. Using simple logic and iterations, we created the splits of passed PDF according to the passed list splits.
5. Adding watermark to PDF pages
Here is how the first page of original (left) and watermarked (right) PDF file looks like:
- All the process is same as the page rotation example. Only difference is:
wmpageObj = add_watermark(mywatermark, pdfReader.getPage(page))
- Page object is converted to watermarked page object using add_watermark() function.
- Let us try to understand add_watermark() function:
wmFileObj = open(wmFile, 'rb') pdfReader = PyPDF2.PdfFileReader(wmFileObj) pageObj.mergePage(pdfReader.getPage(0)) wmFileObj.close() return pageObj
- Foremost, we create a PDF reader object of watermark.pdf. To the passed page object, we use mergePage() function and pass the page object of the first page of the watermark PDF reader object. This will overlay the watermark over the passed page object.
And here we reach the end of this long tutorial on working with PDF files in python.
Now, you can easily create your own PDF manager!
This article is contributed by Nikhil Kumar. If you like GeeksforGeeks and would like to contribute, you can also write an article using write.geeksforgeeks.org or mail your article to email@example.com. See your article appearing on the GeeksforGeeks main page and help other Geeks.
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