PDF Reading with PyPDF2

PyPDF2 is a free and open-source pure-Python PDF library capable of splitting, merging, cropping, and transforming the pages of PDF files. It can also add custom data, viewing options, and passwords to PDF files. While its successor, `pypdf`, is now the actively maintained and recommended library (starting from version 3.0.0, PyPDF2 essentially became `pypdf` version 2.x), many existing projects still utilize PyPDF2. This explanation will focus on PyPDF2 as requested.

Key Features of PyPDF2 for Reading PDFs:
- Reading Text: Extract text content from individual pages of a PDF document. This is useful for data extraction, indexing, or converting PDF content into other formats.
- Page Management: Access specific pages, get the total number of pages, or iterate through all pages.
- Metadata Extraction: Retrieve document information like author, title, subject, creation date, etc.

How it Works:
PyPDF2 reads a PDF file byte by byte, parsing its internal structure to access different elements. For text extraction, it decodes the content streams of each page, which often contain instructions for placing text. It then attempts to reassemble these instructions into readable strings.

Installation:
You can install PyPDF2 using pip:
`pip install PyPDF2`

Limitations:
- Scanned PDFs (Image-based PDFs): PyPDF2 cannot extract text directly from scanned PDF documents because the content is an image, not actual text characters. For such cases, Optical Character Recognition (OCR) tools are required.
- Complex Layouts: While it can extract text, preserving the exact visual layout or handling complex tables and multi-column designs can be challenging, as it primarily extracts raw text strings.
- Forms: It has limited capabilities for interacting with PDF form fields.

In summary, PyPDF2 is a powerful tool for programmatic interaction with PDF files, particularly for reading textual content and manipulating page structures. For new projects, considering `pypdf` (the modern fork) is often recommended due to ongoing maintenance and potential performance improvements.

import PyPDF2
import os

 Define the path to your PDF file
pdf_file_path = "sample.pdf"

 --- IMPORTANT: Please ensure a PDF file named 'sample.pdf' exists in the same directory ---
 --- OR replace "sample.pdf" with the actual path to your PDF file.                       ---
 --- If 'sample.pdf' does not exist, the script will report a FileNotFoundError.         ---

 Example: Reading text from a PDF file using PyPDF2
try:
     Open the PDF file in binary read mode ('rb')
    with open(pdf_file_path, 'rb') as file:
         Create a PdfReader object
        reader = PyPDF2.PdfReader(file)

         Get the total number of pages in the PDF
        num_pages = len(reader.pages)
        print(f"Total pages in '{pdf_file_path}': {num_pages}\n")

         Iterate through each page and extract text
        for page_num in range(num_pages):
            page = reader.pages[page_num]
            text = page.extract_text()

            print(f"--- Page {page_num + 1} ---")
            if text:
                 Print the extracted text. Limit to first 500 chars for brevity if text is long.
                 Newlines within the text are preserved.
                print(text[:500] + "..." if len(text) > 500 else text)
            else:
                print("No text found on this page (might be an image-based PDF or empty page).")
            print("-" - 20)

except FileNotFoundError:
    print(f"Error: The file '{pdf_file_path}' was not found. Please ensure the PDF file exists in the specified path.")
except PyPDF2.errors.PdfReadError:
    print(f"Error: Could not read '{pdf_file_path}'. It might be corrupted or not a valid PDF file.")
except Exception as e:
    print(f"An unexpected error occurred: {e}")