Prompt Engineering Introduction to OpenAI
Published: 2024-04-06 20:32:59

Using Python to Talk to Large Language Models with OpenAI's API
Have you ever wanted to chat with a large language model (LLM)? Well, with OpenAI's API and a little Python know-how, you can! This blog post will walk you through the steps of setting up your environment and interacting with an LLM using OpenAI's chat completion API.
1. Gear Up: Installation Essentials
Before we dive into the code, let's get your Python environment ready. We'll need a couple of libraries:
os: This library provides functions for interacting with the operating system, which will come in handy later.
openai: This is the main library that allows us to interact with OpenAI's API.

You can install these libraries using the pip command in your terminal. Here's the command to install both libraries at once:
Bash
pip install os openai

Use code with caution.
content_copy
2. Obtaining Your OpenAI API Key
To use OpenAI's API, you'll need an API key. If you don't have one already, head over to OpenAI API: https://beta.openai.com/account/api-keys and create an account. Once you're logged in, you can generate a new API key.
3. Setting Up the API Key
Now that you have your API key, it's time to tell Python how to access it. We'll use an environment variable to store the key securely. Here's how to set the environment variable in your terminal (replace YOUR_API_KEY with your actual key):
Bash
export OPENAI_API_KEY=YOUR_API_KEY

Use code with caution.
content_copy
4. Chatting with the LLM: Writing the Python Code
We're finally ready to write some Python code! Here's a breakdown of the steps involved:
Import Libraries: We'll start by importing the os and openai libraries we installed earlier.

Python
import os
import openai

Use code with caution.
content_copy
Setting Up the API Key: Next, we'll use the os library to access the OPENAI_API_KEY environment variable we set up earlier.

Python
openai.api_key = os.getenv("OPENAI_API_KEY")

Use code with caution.
content_copy
Crafting the Conversation: Now comes the fun part! We'll use the openai.Completion.create function to interact with the LLM. This function takes a few arguments:
model: This specifies the LLM you want to use. OpenAI offers different models with varying capabilities. We'll use "text-davinci-003" as an example in this post.
messages: This is a list of messages that will form the conversation. Each message has two parts:
role: This indicates who said the message (e.g., "user" for you, "assistant" for the LLM).
content: This is the actual text of the message. For instance, you might start with a message like: {"role": "user", "content": "Hi there!"}

temperature: This controls the randomness of the LLM's responses. Lower values result in more consistent responses, while higher values can lead to more creative but surprising outputs.
max_tokens: This limits the number of tokens (think of them as words or characters) the LLM can generate in its response.

Here's an example of how you might use the openai.Completion.create function:
Python
response = openai.Completion.create(
    model="text-davinci-003",
    messages=[
        {"role": "user", "content": "Hi! How can you help me today?"}
    ],
    temperature=0.7,
    max_tokens=150
)

Use code with caution.
content_copy
Understanding the Response: Once you run the code, the response variable will contain the LLM's response, along with details like the number of tokens used. You can then print the response to see what the LLM has to say!

5. Token Talk: Understanding Tokenization
The OpenAI API uses tokens to measure the length of text. Roughly, four characters of text correspond to one token. This is important to consider when setting the max_tokens parameter in the openai.Completion.create function.
That's it! With these steps, you can start chatting with an LLM using Python and OpenAI's API. Remember to experiment with different models, temperatures, and prompts to see how they affect the conversation. Happy chatting!