Source code for langchain.chains.graph_qa.cypher
"""Question answering over a graph."""
from __future__ import annotations
import re
from typing import Any, Dict, List, Optional
from pydantic import Field
from langchain.base_language import BaseLanguageModel
from langchain.callbacks.manager import CallbackManagerForChainRun
from langchain.chains.base import Chain
from langchain.chains.graph_qa.prompts import CYPHER_GENERATION_PROMPT, CYPHER_QA_PROMPT
from langchain.chains.llm import LLMChain
from langchain.graphs.neo4j_graph import Neo4jGraph
from langchain.prompts.base import BasePromptTemplate
INTERMEDIATE_STEPS_KEY = "intermediate_steps"
def extract_cypher(text: str) -> str:
    # The pattern to find Cypher code enclosed in triple backticks
    pattern = r"```(.*?)```"
    # Find all matches in the input text
    matches = re.findall(pattern, text, re.DOTALL)
    return matches[0] if matches else text
[docs]class GraphCypherQAChain(Chain):
    """Chain for question-answering against a graph by generating Cypher statements."""
    graph: Neo4jGraph = Field(exclude=True)
    cypher_generation_chain: LLMChain
    qa_chain: LLMChain
    input_key: str = "query"  #: :meta private:
    output_key: str = "result"  #: :meta private:
    top_k: int = 10
    """Number of results to return from the query"""
    return_intermediate_steps: bool = False
    """Whether or not to return the intermediate steps along with the final answer."""
    return_direct: bool = False
    """Whether or not to return the result of querying the graph directly."""
rtdocs_stable/api.python.langchain.com/en/stable/_modules/langchain/chains/graph_qa/cypher.html