OpenAI embeddings in LangChain - Mini Project: Build & Apply

Using OpenAI Embeddings with Langchain

📖 Scenario: You want to create a small program that uses OpenAI's text embeddings to convert a list of sentences into vectors. These vectors can help you compare sentence meanings later.

🎯 Goal: Build a Python script using Langchain that creates OpenAI embeddings for a list of sentences.

📋 What You'll Learn

Create a list of sentences called texts with exact values

Create a variable called embedding_model that initializes OpenAIEmbeddings

Use embedding_model.embed_documents to get embeddings for texts

Store the embeddings in a variable called embeddings

💡 Why This Matters

🌍 Real World

Embedding text is useful for search, recommendations, and understanding text meaning in many apps.

💼 Career

Many AI and data jobs require creating and using embeddings to build smart features.

1

Create the list of sentences

Create a list called texts with these exact strings: 'Hello world', 'Langchain is great', and 'OpenAI embeddings are useful'.

LangChain

# Create the list of sentences called texts
# Your code here

Hint

Use square brackets to create a list and include the exact strings separated by commas.

2

Initialize the OpenAI embeddings model

Create a variable called embedding_model and set it to OpenAIEmbeddings() from langchain.embeddings.openai. Assume the import is done.

LangChain

texts = ['Hello world', 'Langchain is great', 'OpenAI embeddings are useful']
# Initialize embedding_model with OpenAIEmbeddings()
# Your code here

Hint

Use embedding_model = OpenAIEmbeddings() to create the embeddings object.

3

Generate embeddings for the sentences

Use embedding_model.embed_documents(texts) to create embeddings for the list texts. Store the result in a variable called embeddings.

LangChain

from langchain.embeddings.openai import OpenAIEmbeddings

texts = ['Hello world', 'Langchain is great', 'OpenAI embeddings are useful']
embedding_model = OpenAIEmbeddings()
# Generate embeddings for texts and store in embeddings
# Your code here

Hint

Call embed_documents on embedding_model with texts as argument.

4

Complete the script with a comment

Add a comment at the end of the script that says # Embeddings are ready to use.

LangChain

from langchain.embeddings.openai import OpenAIEmbeddings

texts = ['Hello world', 'Langchain is great', 'OpenAI embeddings are useful']
embedding_model = OpenAIEmbeddings()
embeddings = embedding_model.embed_documents(texts)
# Add a comment that embeddings are ready
# Your code here

Hint

Just add the exact comment line at the end.

Practice

1. What is the main purpose of OpenAI embeddings in Langchain?

easy

A. To convert text into numerical vectors that represent meaning

B. To generate images from text descriptions

C. To translate text from one language to another

D. To create user interfaces automatically

Solution

1. Step 1: Understand what embeddings do

   Embeddings turn text into lists of numbers that capture the meaning of the text.

2. Step 2: Identify the purpose in Langchain

   Langchain uses embeddings to help computers find similar or related texts easily by comparing these number lists.

3. Final Answer:

   To convert text into numerical vectors that represent meaning -> Option A

4. Quick Check:

   Embeddings = numerical meaning vectors [OK]

Hint: Embeddings = text to numbers showing meaning [OK]

Common Mistakes:

• Confusing embeddings with image generation
• Thinking embeddings translate languages
• Assuming embeddings create UI elements

2. Which of the following is the correct way to create OpenAI embeddings using Langchain in Python?

easy

A. import OpenAI from langchain
embeddings = OpenAI.create_embeddings()

B. import langchain
embeddings = langchain.OpenAIEmbeddings()

C. from langchain import embeddings
embeddings = embeddings.OpenAI()

D. from langchain.embeddings import OpenAIEmbeddings
embeddings = OpenAIEmbeddings()

Solution

1. Step 1: Check the import statement

   The correct import is from langchain.embeddings import OpenAIEmbeddings.

2. Step 2: Check the instantiation

   Creating embeddings is done by calling OpenAIEmbeddings() with parentheses.

3. Final Answer:

   from langchain.embeddings import OpenAIEmbeddings\nembeddings = OpenAIEmbeddings() -> Option D

4. Quick Check:

   Correct import and instantiation syntax [OK]

Hint: Import from langchain.embeddings, then call OpenAIEmbeddings() [OK]

Common Mistakes:

• Wrong import path or module
• Missing parentheses when creating embeddings
• Using incorrect method names

3. Given the code snippet:

from langchain.embeddings import OpenAIEmbeddings
embeddings = OpenAIEmbeddings()
vector = embeddings.embed_query('Hello world')

What is the type of vector?

medium

A. A dictionary with text keys and values

B. A string containing the original text

C. A list of numbers representing the text meaning

D. An integer representing text length

Solution

1. Step 1: Understand embed_query output

   The embed_query method returns a list of numbers (a vector) representing the meaning of the input text.

2. Step 2: Identify the type of vector

   Since it encodes meaning, the vector is a list of floats or numbers, not a string or dictionary.

3. Final Answer:

   A list of numbers representing the text meaning -> Option C

4. Quick Check:

   embed_query output = number list [OK]

Hint: embed_query returns a number list vector [OK]

Common Mistakes:

• Expecting a string instead of numbers
• Thinking it returns a dictionary
• Assuming it returns text length as integer

4. What is wrong with this code snippet for creating embeddings?

from langchain.embeddings import OpenAIEmbeddings
embeddings = OpenAIEmbeddings
vector = embeddings.embed_query('Test')

medium

A. embed_query method does not exist

B. Missing parentheses when creating OpenAIEmbeddings instance

C. Incorrect import statement

D. The input text must be a list, not a string

Solution

1. Step 1: Check how embeddings instance is created

   The code assigns OpenAIEmbeddings without parentheses, so embeddings is a class, not an instance.

2. Step 2: Understand the impact on embed_query call

   Calling embed_query on the class (not instance) will cause an error because methods need an instance.

3. Final Answer:

   Missing parentheses when creating OpenAIEmbeddings instance -> Option B

4. Quick Check:

   Instantiate with () to call methods [OK]

Hint: Always add () to create instance before method calls [OK]

Common Mistakes:

• Forgetting parentheses when creating instances
• Assuming methods work on classes directly
• Misreading import statements

5. You want to find the most similar text from a list using OpenAI embeddings in Langchain. Which approach correctly uses embeddings to compare similarity?

hard

A. Create embeddings for all texts, then compute cosine similarity between vectors

B. Compare texts directly as strings using == operator

C. Use embed_query only on the first text and compare lengths

D. Generate embeddings but do not compare vectors

Solution

1. Step 1: Understand how similarity is found with embeddings

   Embeddings convert texts into vectors; similarity is measured by comparing these vectors, often with cosine similarity.

2. Step 2: Identify correct approach to find most similar text

   Create embeddings for all texts, then compute similarity scores between vectors to find the closest match.

3. Final Answer:

   Create embeddings for all texts, then compute cosine similarity between vectors -> Option A

4. Quick Check:

   Similarity = compare embedding vectors [OK]

Hint: Compare vector embeddings with cosine similarity [OK]

Common Mistakes:

• Comparing raw strings instead of vectors
• Using embed_query on only one text
• Not comparing embeddings at all