Langchain: ModuleNotFoundError: No module named 'langchain'

Question:

When I write code in VS Code, beginning with:

import os
from langchain.chains import RetrievalQA
from langchain.llms import OpenAI
from langchain.document_loaders import TextLoader

I am met with the error: ModuleNotFoundError: No module named 'langchain'

I have updated my Python to version 3.11.4, have updated pip, and reinstalled langchain. I have also checked sys.path and the folder C:\Python311\Lib\site-packages in which the Langchain folder is, is appended.

EDIT: Langchain import works when I run it in the Python console (functionality works too), but when I run the code from the VSCode run button it still provides the ModuleNotFoundError.

Has anyone else run into this issue and found a solution?

Asked By: anonymousqs

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Source

Answers:

you probably didn’t put your python file location into the enviroment variables.

copy your python file location
go to search>edit enviroment enviroment variables>user variables>path>new
put the copied python location in the user variables.
then try again!

Answered By: DarkStar

when installing in your environment try using:
python -m pip install langchain

Answered By: Jorge M

For future reference, I’m fairly sure this error was caused by pip installing files in the incorrect directory. Make sure the target directory is where your sys.path folder is, as sometimes these can vary! Thanks to everyone who provided advice.

Answered By: anonymousqs

If you are running the code in VS and you have more than one Python version, please check if the bottom right side of the VS Window the version of Python you are using.

Answered By: waloar

I had installed packages with python 3.9.7 but this version was causing issues so I switched to Python 3.10. When I installed the langhcain it was in python 3.9.7 directory. If yo run pip show langchain, you get this

Name: langchain
Version: 0.0.220
Summary: Building applications with LLMs through composability
Home-page: https://www.github.com/hwchase17/langchain
Author: 
Author-email: 
License: MIT
Location: /home/anaconda3/lib/python3.9/site-packages
Requires: aiohttp, async-timeout, dataclasses-json, langchainplus-sdk, numexpr, numpy, openapi-schema-pydantic, pydantic, PyYAML, requests, SQLAlchemy, tenacity
Required-by: jupyter_ai, jupyter_ai_magics

If you look at the Location property, you see this /home/anaconda3/lib/python3.9/site-packages. But since I am using Pyhton3.10 I had to make sure langchain is in the directory of Python 3.10. so installed the langhchain with

python3.10 -m pip install langchain

now when I run, python3.10 -m pip show langchain I get this

Name: langchain
Version: 0.0.264
Summary: Building applications with LLMs through composability
Home-page: https://www.github.com/hwchase17/langchain
Author: 
Author-email: 
License: MIT
Location: /home/.local/lib/python3.10/site-packages
Requires: aiohttp, async-timeout, dataclasses-json, langsmith, numexpr, numpy, openapi-schema-pydantic, pydantic, PyYAML, requests, SQLAlchemy, tenacity
Required-by:

Now new Location is referring to Python3.10 directory

Answered By: Yilmaz

Solved the issue by creating a virtual environment first and then installing langchain.

Open an empty folder in VSCode then in terminal:

  1. Create a new virtual environment python -m venv myvirtenv where myvirtenv is the name of your virtual environment.

  2. In terminal type myvirtenv/Scripts/activate to activate your virtual environment. (If this does not work then type cd .myvirtenvScripts and hit enter, type ./activate hit enter and then type cd ../.. ) . Now your virtual environment should be activated in VScode.

  3. Type pip install langchain and hit enter.

Answered By: raiyan22
!pip install langchain

Install the Langchain libary.

You can install it by using pip and go in your terminal and type in the code

Answered By: fgfff