retrievers

Retriever class returns Documents given a text query.

It is more general than a vector store. A retriever does not need to be able to store documents, only to return (or retrieve) it. Vector stores can be used as the backbone of a retriever, but there are other types of retrievers as well.

Class hierarchy:

BaseRetriever --> <name>Retriever  # Examples: ArxivRetriever, MergerRetriever

Main helpers:

Document, Serializable, Callbacks,
CallbackManagerForRetrieverRun, AsyncCallbackManagerForRetrieverRun

Classes

retrievers.arcee.ArceeRetriever	Arcee Domain Adapted Language Models (DALMs) retriever.
retrievers.arxiv.ArxivRetriever	Arxiv retriever.
retrievers.asknews.AskNewsRetriever	AskNews retriever.
retrievers.azure_ai_search.AzureAISearchRetriever	Azure AI Search service retriever.
retrievers.azure_ai_search.AzureCognitiveSearchRetriever	Azure Cognitive Search service retriever.
retrievers.bedrock.AmazonKnowledgeBasesRetriever	Amazon Bedrock Knowledge Bases retriever.
retrievers.bedrock.RetrievalConfig	Configuration for retrieval.
retrievers.bedrock.VectorSearchConfig	Configuration for vector search.
retrievers.bm25.BM25Retriever	BM25 retriever without Elasticsearch.
retrievers.breebs.BreebsRetriever	A retriever class for Breebs.
retrievers.chaindesk.ChaindeskRetriever	Chaindesk API retriever.
retrievers.chatgpt_plugin_retriever.ChatGPTPluginRetriever	ChatGPT plugin retriever.
retrievers.databerry.DataberryRetriever	Databerry API retriever.
retrievers.docarray.DocArrayRetriever	DocArray Document Indices retriever.
retrievers.docarray.SearchType(value[, ...])	Enumerator of the types of search to perform.
retrievers.dria_index.DriaRetriever	Dria retriever using the DriaAPIWrapper.
retrievers.elastic_search_bm25.ElasticSearchBM25Retriever	Elasticsearch retriever that uses BM25.
retrievers.embedchain.EmbedchainRetriever	Embedchain retriever.
retrievers.google_vertex_ai_search.GoogleCloudEnterpriseSearchRetriever	Google Vertex Search API retriever alias for backwards compatibility.
retrievers.kay.KayAiRetriever	Retriever for Kay.ai datasets.
retrievers.kendra.AdditionalResultAttribute	Additional result attribute.
retrievers.kendra.AdditionalResultAttributeValue	Value of an additional result attribute.
retrievers.kendra.AmazonKendraRetriever	Amazon Kendra Index retriever.
retrievers.kendra.DocumentAttribute	Document attribute.
retrievers.kendra.DocumentAttributeValue	Value of a document attribute.
retrievers.kendra.Highlight	Information that highlights the keywords in the excerpt.
retrievers.kendra.QueryResult	Amazon Kendra Query API search result.
retrievers.kendra.QueryResultItem	Query API result item.
retrievers.kendra.ResultItem	Base class of a result item.
retrievers.kendra.RetrieveResult	Amazon Kendra Retrieve API search result.
retrievers.kendra.RetrieveResultItem	Retrieve API result item.
retrievers.kendra.TextWithHighLights	Text with highlights.
retrievers.knn.KNNRetriever	KNN retriever.
retrievers.llama_index.LlamaIndexGraphRetriever	LlamaIndex graph data structure retriever.
retrievers.llama_index.LlamaIndexRetriever	LlamaIndex retriever.
retrievers.metal.MetalRetriever	Metal API retriever.
retrievers.milvus.MilvusRetriever	Milvus API retriever.
retrievers.nanopq.NanoPQRetriever	`NanoPQ retriever.
retrievers.outline.OutlineRetriever	Retriever for Outline API.
retrievers.pinecone_hybrid_search.PineconeHybridSearchRetriever	Pinecone Hybrid Search retriever.
retrievers.pubmed.PubMedRetriever	PubMed API retriever.
retrievers.rememberizer.RememberizerRetriever	Rememberizer retriever.
retrievers.remote_retriever.RemoteLangChainRetriever	LangChain API retriever.
retrievers.svm.SVMRetriever	SVM retriever.
retrievers.tavily_search_api.SearchDepth(value)	Search depth as enumerator.
retrievers.tavily_search_api.TavilySearchAPIRetriever	Tavily Search API retriever.
retrievers.tfidf.TFIDFRetriever	TF-IDF retriever.
retrievers.thirdai_neuraldb.NeuralDBRetriever	Document retriever that uses ThirdAI's NeuralDB.
retrievers.vespa_retriever.VespaRetriever	Vespa retriever.
retrievers.weaviate_hybrid_search.WeaviateHybridSearchRetriever	Weaviate hybrid search retriever.
retrievers.web_research.QuestionListOutputParser	Output parser for a list of numbered questions.
retrievers.web_research.SearchQueries	Search queries to research for the user's goal.
retrievers.web_research.WebResearchRetriever	Google Search API retriever.
retrievers.wikipedia.WikipediaRetriever	Wikipedia API retriever.
retrievers.you.YouRetriever	You.com Search API retriever.
retrievers.zep.SearchScope(value[, names, ...])	Which documents to search.
retrievers.zep.SearchType(value[, names, ...])	Enumerator of the types of search to perform.
retrievers.zep.ZepRetriever	Zep MemoryStore Retriever.
retrievers.zep_cloud.ZepCloudRetriever	Zep Cloud MemoryStore Retriever.
retrievers.zilliz.ZillizRetriever	Zilliz API retriever.

Functions

retrievers.bm25.default_preprocessing_func(text)
retrievers.kendra.clean_excerpt(excerpt)	Clean an excerpt from Kendra.
retrievers.kendra.combined_text(item)	Combine a ResultItem title and excerpt into a single string.
retrievers.knn.create_index(contexts, embeddings)	Create an index of embeddings for a list of contexts.
retrievers.milvus.MilvusRetreiver(*args, ...)	Deprecated MilvusRetreiver.
retrievers.nanopq.create_index(contexts, ...)	Create an index of embeddings for a list of contexts.
retrievers.pinecone_hybrid_search.create_index(...)	Create an index from a list of contexts.
retrievers.pinecone_hybrid_search.hash_text(text)	Hash a text using SHA256.
retrievers.svm.create_index(contexts, embeddings)	Create an index of embeddings for a list of contexts.
retrievers.zilliz.ZillizRetreiver(*args, ...)	Deprecated ZillizRetreiver.

Deprecated classes

retrievers.cohere_rag_retriever.CohereRagRetriever	Deprecated since version 0.0.30: Use langchain_cohere.CohereRagRetriever instead.
retrievers.google_cloud_documentai_warehouse.GoogleDocumentAIWarehouseRetriever	Deprecated since version 0.0.32: Use langchain_google_community.DocumentAIWarehouseRetriever instead.
retrievers.google_vertex_ai_search.GoogleVertexAIMultiTurnSearchRetriever	Deprecated since version 0.0.33: Use langchain_google_community.VertexAIMultiTurnSearchRetriever instead.
retrievers.google_vertex_ai_search.GoogleVertexAISearchRetriever	Deprecated since version 0.0.33: Use langchain_google_community.VertexAISearchRetriever instead.
retrievers.qdrant_sparse_vector_retriever.QdrantSparseVectorRetriever	Deprecated since version 0.2.16: Use Qdrant vector store now supports sparse retrievals natively. Use langchain_qdrant.QdrantVectorStore#as_retriever() instead. Reference: https://python.langchain.com/v0.2/docs/integrations/vectorstores/qdrant/#sparse-vector-search instead.