How to use langchain?

Leon Chase

• 1 min read

To use LangChain, follow these steps:

  1. Install LangChain and Dependencies:
    • Install LangChain using pip install langchain.
    • For integrations like OpenAI, install the OpenAI package with pip install openai[2][4].
  2. Set Up Your Environment:
    • Obtain an API key from your chosen LLM provider (e.g., OpenAI).
    • Import necessary modules in your Python script[2][4].
  3. Create a Prompt Template:
    • Use PromptTemplate to define your prompts with input variables[5][4].
  4. Invoke the LLM:
    • Create an instance of the LLM (e.g., OpenAI) and invoke it with your prompt[2][4].
  5. Build Applications:
    • Use LangChain components like LLMChain and ConversationChain to build more complex applications[1][3].
      Here's a simple example using OpenAI:
from langchain.llms import OpenAI
llm = OpenAI(openai_api_key="YOUR_API_KEY")
response = llm.invoke("What is the capital of France?")
print(response)

Replace "YOUR_API_KEY" with your actual OpenAI API key.
Citations:
[1] Quickstart - ️ LangChain https://python.langchain.com/v0.1/docs/get_started/quickstart/
[2] Getting started with LangChain: How to run your first application https://www.pluralsight.com/resources/blog/ai-and-data/getting-started-langchain
[3] A Beginner's Guide to LangChain | Build Real-Time AI Applications ... https://www.singlestore.com/blog/beginners-guide-to-langchain/
[4] What Is LangChain and How to Use It: A Guide - TechTarget https://www.techtarget.com/searchenterpriseai/definition/LangChain
[5] LangChain: Introduction and Getting Started | Pinecone https://www.pinecone.io/learn/series/langchain/langchain-intro/
[6] LangChain: How to Use - Beginner's Guide | Step-by-Step Tutorial https://www.youtube.com/watch?v=n-FzBaUO3Dc
[7] How to Use LangChain to Build With LLMs – A Beginner's Guide https://www.freecodecamp.org/news/beginners-guide-to-langchain/
[8] How-to guides - ️ LangChain https://python.langchain.com/docs/how_to/