Gaining Deep Insights with Conversational Q&A Using Python

Unlocking the potential of LLMs using LangChain and Python to extract valuable insights from PDF documents

Source: Author


In today’s digital era, the ability to efficiently extract information from PDF documents is crucial for businesses, researchers, and professionals across various domains. PDFs are widely used for sharing reports, research papers, invoices, and more, making them a treasure trove of valuable data. However, the traditional methods of parsing and extracting information from PDFs often involve complex programming and data manipulation. Enter Large Language Models (LLMs) and LangChain, which revolutionize the way we approach PDF information extraction. In this blog, we will explore how Python, combined with LLMs and Langchain, empowers us to effortlessly unlock insights hidden within PDF documents.

In this blog, we will cover the below topics

  • Understanding Large Language Models (LLMs)
  • Implementing PDF Information Extraction in Python
    – Setting Up the Environment
    – Installing Dependencies
  • Extracting Information from PDFs with LLM and Langchain
    – Preprocessing the PDFs
    – Using LLMs for Text Extraction
    – Leveraging Langchain for Enhanced NLP
  • Conclusion

Understanding Large Language Models

Large Language Models, such as OpenAI’s GPT-3.5, are state-of-the-art AI models that have been trained on massive amounts of text data. These models possess the remarkable ability to understand and generate human-like language. By leveraging pre-trained LLMs, we can utilize their language comprehension capabilities to extract information from PDFs with relative ease.

What is Langchain?

Langchain is a cutting-edge framework built on large language models that enables prompt engineering and empowers developers to create applications that interact seamlessly with users in natural language. It provides a structured way to incorporate prompts and generate responses from large language models, making it easier to build intelligent and interactive applications. The LangChain contains modules that are wrappers to other popular language models like Hugging Face and OpenAI.

Python: The Swiss Army Knife for PDF Manipulation

Python, with its vast array of libraries and tools, has become the go-to language for data extraction tasks. It provides several libraries specifically designed for working with PDF documents, such as PyPDF2, PDFMiner, and Slate. These libraries enable us to read, parse, and extract data from PDF files effortlessly. In this case, we will be using pyPDF2.

from PyPDF2 import PdfReader
from langchain.embeddings.openai import OpenAIEmbeddings
from langchain.text_splitter import CharacterTextSplitter
from langchain.vectorstores import FAISS

import os
os.environ["OPENAI_API_KEY"] = "YOUR openai API KEY"

Step 1: Parsing PDFs with Python

The first step in extracting information from PDFs is parsing the documents. With the help of PyPDF2, we can extract text, images, tables, and other elements from PDFs. These libraries provide intuitive methods to navigate the PDF’s structure and retrieve the desired information. We will be using the “ICC-Playing-Conditions-ICC-World-Test-Championship-2021–2023-July-2021” pdf doc to query the document.

pdfreader = PdfReader('ICC-Playing-Conditions-ICC-World-Test-Championship-

from typing_extensions import Concatenate
# read text from pdf
raw_text = ''
for i, page in enumerate(pdfreader.pages):
content = page.extract_text()
if content:
raw_text += content

Step 2: Leveraging Large Language Models

Once we have extracted the text from the PDF, we can leverage the power of LLMs to comprehend and analyze the content. Python libraries like the OpenAI API or Hugging Face’s transformers allow us to interact with LLMs effortlessly. We can use these libraries to perform tasks such as language translation, summarization, sentiment analysis, or even question-answering on the extracted text. In this case, we will use OpenAI API.

text_splitter = CharacterTextSplitter(
separator = "\n",
chunk_size = 800,
chunk_overlap = 200,
length_function = len,
texts = text_splitter.split_text(raw_text)

Step 3: Introducing LangChain for Enhanced PDF Information Extraction

To further enhance the capabilities of PDF information extraction, we can integrate LangChain into our workflow. LangChain is a blockchain-based decentralized network that facilitates secure and transparent data sharing. By utilizing Langchain, we can securely store and share extracted data from PDFs. This decentralized approach enhances the reliability and integrity of the extracted information.

from langchain.chains.question_answering import load_qa_chain
from langchain.llms import OpenAI

embeddings = OpenAIEmbeddings()
document_search = FAISS.from_texts(texts, embeddings)

chain = load_qa_chain(OpenAI(), chain_type="stuff")

Our setup is ready for conversing with pdf documents. Let’s try a few queries.

Query 1:

query = "Who submits the concussion report"
docs = document_search.similarity_search(query), question=query)

The Team Medical Representative or Team Manager.

Here is the snippet from the guideline document, the model gave us the first 3 lines from the below paragraph.

Source: ICC Guidelines

Query 2:

query = "What is the size of the cricket ball"

The cricket ball must weigh between 5.5 ounces/155.9 g and 5.75 ounces/163 g,
and must measure between 8.81 in/22.4 cm and 9 in/22.9 cm in circumference.
Source: ICC Guidelines

Benefits of Conversational Document Q&A

  1. Efficiency: Conversational document Q&A eliminates the need for manual searching and reading through lengthy documents. Users can directly ask questions and receive specific answers, saving time and effort.
  2. Accessibility: It provides a user-friendly and accessible way to interact with complex documents. Users with varying levels of expertise can easily retrieve information without having to navigate through the entire document.
  3. Precision: The system can accurately pinpoint relevant information within documents, ensuring precise answers to user queries. It reduces the risk of misinterpretation or overlooking important details.
  4. Scalability: Conversational document Q&A can handle a large volume of documents and queries simultaneously, making it suitable for organizations with extensive document repositories or knowledge bases.
  5. Collaboration: It promotes collaboration by allowing users to share and discuss information extracted from documents. Multiple users can converse around the document content, fostering knowledge-sharing and decision-making.
  6. Automation: By automating the process of retrieving information from documents, conversational document Q&A reduces the need for manual intervention and enables efficient workflows.
  7. Insights: Analyzing the questions asked and the answers provided can generate valuable insights about user information needs, document relevance, and potential knowledge gaps. This data can inform content improvement strategies and identify areas for further research.


Python, along with its versatile PDF manipulation libraries, enables efficient extraction of insights from PDF documents. By parsing and extracting text from PDFs, Python allows easy comprehension and analysis of the content with LLMs. LangChain facilitates collaboration among multiple LLMs, enhancing accuracy and comprehensiveness. This powerful combination automates and streamlines the previously labor-intensive task of extracting information from PDFs. It unlocks the hidden potential within these documents, empowering businesses and individuals to uncover valuable data and insights.

I hope you liked the article and found it helpful.

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