Source code for langchain_community.retrievers.wikipedia
from typing import List
from langchain_core.callbacks import CallbackManagerForRetrieverRun
from langchain_core.documents import Document
from langchain_core.retrievers import BaseRetriever
from langchain_community.utilities.wikipedia import WikipediaAPIWrapper
[docs]class WikipediaRetriever(BaseRetriever, WikipediaAPIWrapper):
"""`Wikipedia API` retriever.
Setup:
Install the ``wikipedia`` dependency:
.. code-block:: bash
pip install -U wikipedia
Instantiate:
.. code-block:: python
from langchain_community.retrievers import WikipediaRetriever
retriever = WikipediaRetriever()
Usage:
.. code-block:: python
docs = retriever.invoke("TOKYO GHOUL")
print(docs[0].page_content[:100])
.. code-block:: none
Tokyo Ghoul (Japanese: 東京喰種(トーキョーグール), Hepburn: Tōkyō Gūru) is a Japanese dark fantasy
Use within a chain:
.. code-block:: python
from langchain_core.output_parsers import StrOutputParser
from langchain_core.prompts import ChatPromptTemplate
from langchain_core.runnables import RunnablePassthrough
from langchain_openai import ChatOpenAI
prompt = ChatPromptTemplate.from_template(
\"\"\"Answer the question based only on the context provided.
Context: {context}
Question: {question}\"\"\"
)
llm = ChatOpenAI(model="gpt-3.5-turbo-0125")
def format_docs(docs):
return "\\n\\n".join(doc.page_content for doc in docs)
chain = (
{"context": retriever | format_docs, "question": RunnablePassthrough()}
| prompt
| llm
| StrOutputParser()
)
chain.invoke(
"Who is the main character in `Tokyo Ghoul` and does he transform into a ghoul?"
)
.. code-block:: none
'The main character in Tokyo Ghoul is Ken Kaneki, who transforms into a ghoul after receiving an organ transplant from a ghoul named Rize.'
""" # noqa: E501
def _get_relevant_documents(
self, query: str, *, run_manager: CallbackManagerForRetrieverRun
) -> List[Document]:
return self.load(query=query)