.ipynb
.pdf
2Markdown
2Markdown#
2markdown service transforms website content into structured markdown files.
# You will need to get your own API key. See https://2markdown.com/login
api_key = ""
from langchain.document_loaders import ToMarkdownLoader
loader = ToMarkdownLoader.from_api_key(url="https://python.langchain.com/en/latest/", api_key=api_key)
docs = loader.load()
print(docs[0].page_content)
## Contents
- [Getting Started](#getting-started)
- [Modules](#modules)
- [Use Cases](#use-cases)
- [Reference Docs](#reference-docs)
- [LangChain Ecosystem](#langchain-ecosystem)
- [Additional Resources](#additional-resources)
## Welcome to LangChain [\#](\#welcome-to-langchain "Permalink to this headline")
**LangChain** is a framework for developing applications powered by language models. We believe that the most powerful and differentiated applications will not only call out to a language model, but will also be:
1. _Data-aware_: connect a language model to other sources of data
2. _Agentic_: allow a language model to interact with its environment
The LangChain framework is designed around these principles.
This is the Python specific portion of the documentation. For a purely conceptual guide to LangChain, see [here](https://docs.langchain.com/docs/). For the JavaScript documentation, see [here](https://js.langchain.com/docs/).
## Getting Started [\#](\#getting-started "Permalink to this headline")
How to get started using LangChain to create an Language Model application.
- [Quickstart Guide](https://python.langchain.com/en/latest/getting_started/getting_started.html)
Concepts and terminology.
Concepts and terminology.
- [Concepts and terminology](https://python.langchain.com/en/latest/getting_started/concepts.html)
Tutorials created by community experts and presented on YouTube.
- [Tutorials](https://python.langchain.com/en/latest/getting_started/tutorials.html)
## Modules [\#](\#modules "Permalink to this headline")
These modules are the core abstractions which we view as the building blocks of any LLM-powered application.
For each module LangChain provides standard, extendable interfaces. LanghChain also provides external integrations and even end-to-end implementations for off-the-shelf use.
The docs for each module contain quickstart examples, how-to guides, reference docs, and conceptual guides.
The modules are (from least to most complex):
- [Models](https://python.langchain.com/en/latest/modules/models.html): Supported model types and integrations.
- [Prompts](https://python.langchain.com/en/latest/modules/prompts.html): Prompt management, optimization, and serialization.
- [Memory](https://python.langchain.com/en/latest/modules/memory.html): Memory refers to state that is persisted between calls of a chain/agent.
- [Indexes](https://python.langchain.com/en/latest/modules/indexes.html): Language models become much more powerful when combined with application-specific data - this module contains interfaces and integrations for loading, querying and updating external data.
- [Chains](https://python.langchain.com/en/latest/modules/chains.html): Chains are structured sequences of calls (to an LLM or to a different utility).
- [Agents](https://python.langchain.com/en/latest/modules/agents.html): An agent is a Chain in which an LLM, given a high-level directive and a set of tools, repeatedly decides an action, executes the action and observes the outcome until the high-level directive is complete.
- [Callbacks](https://python.langchain.com/en/latest/modules/callbacks/getting_started.html): Callbacks let you log and stream the intermediate steps of any chain, making it easy to observe, debug, and evaluate the internals of an application.
## Use Cases [\#](\#use-cases "Permalink to this headline")
Best practices and built-in implementations for common LangChain use cases:
- [Autonomous Agents](https://python.langchain.com/en/latest/use_cases/autonomous_agents.html): Autonomous agents are long-running agents that take many steps in an attempt to accomplish an objective. Examples include AutoGPT and BabyAGI.
- [Agent Simulations](https://python.langchain.com/en/latest/use_cases/agent_simulations.html): Putting agents in a sandbox and observing how they interact with each other and react to events can be an effective way to evaluate their long-range reasoning and planning abilities.
- [Personal Assistants](https://python.langchain.com/en/latest/use_cases/personal_assistants.html): One of the primary LangChain use cases. Personal assistants need to take actions, remember interactions, and have knowledge about your data.
- [Question Answering](https://python.langchain.com/en/latest/use_cases/question_answering.html): Another common LangChain use case. Answering questions over specific documents, only utilizing the information in those documents to construct an answer.
- [Chatbots](https://python.langchain.com/en/latest/use_cases/chatbots.html): Language models love to chat, making this a very natural use of them.
- [Querying Tabular Data](https://python.langchain.com/en/latest/use_cases/tabular.html): Recommended reading if you want to use language models to query structured data (CSVs, SQL, dataframes, etc).
- [Code Understanding](https://python.langchain.com/en/latest/use_cases/code.html): Recommended reading if you want to use language models to analyze code.
- [Interacting with APIs](https://python.langchain.com/en/latest/use_cases/apis.html): Enabling language models to interact with APIs is extremely powerful. It gives them access to up-to-date information and allows them to take actions.
- [Extraction](https://python.langchain.com/en/latest/use_cases/extraction.html): Extract structured information from text.
- [Summarization](https://python.langchain.com/en/latest/use_cases/summarization.html): Compressing longer documents. A type of Data-Augmented Generation.
- [Evaluation](https://python.langchain.com/en/latest/use_cases/evaluation.html): Generative models are hard to evaluate with traditional metrics. One promising approach is to use language models themselves to do the evaluation.
## Reference Docs [\#](\#reference-docs "Permalink to this headline")
Full documentation on all methods, classes, installation methods, and integration setups for LangChain.
- [Reference Documentation](https://python.langchain.com/en/latest/reference.html)
## LangChain Ecosystem [\#](\#langchain-ecosystem "Permalink to this headline")
Guides for how other companies/products can be used with LangChain.
- [LangChain Ecosystem](https://python.langchain.com/en/latest/ecosystem.html)
## Additional Resources [\#](\#additional-resources "Permalink to this headline")
Additional resources we think may be useful as you develop your application!
- [LangChainHub](https://github.com/hwchase17/langchain-hub): The LangChainHub is a place to share and explore other prompts, chains, and agents.
- [Gallery](https://python.langchain.com/en/latest/additional_resources/gallery.html): A collection of our favorite projects that use LangChain. Useful for finding inspiration or seeing how things were done in other applications.
- [Deployments](https://python.langchain.com/en/latest/additional_resources/deployments.html): A collection of instructions, code snippets, and template repositories for deploying LangChain apps.
- [Tracing](https://python.langchain.com/en/latest/additional_resources/tracing.html): A guide on using tracing in LangChain to visualize the execution of chains and agents.
- [Model Laboratory](https://python.langchain.com/en/latest/additional_resources/model_laboratory.html): Experimenting with different prompts, models, and chains is a big part of developing the best possible application. The ModelLaboratory makes it easy to do so.
- [Discord](https://discord.gg/6adMQxSpJS): Join us on our Discord to discuss all things LangChain!
- [YouTube](https://python.langchain.com/en/latest/additional_resources/youtube.html): A collection of the LangChain tutorials and videos.
- [Production Support](https://forms.gle/57d8AmXBYp8PP8tZA): As you move your LangChains into production, we’d love to offer more comprehensive support. Please fill out this form and we’ll set up a dedicated support Slack channel.

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By Harrison Chase