AI Agents with LangGraph
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Open the empty state-demo.ipynb notebook in the Starter folder. You’ll make a graph that adds toppings to a pizza. First, define your State class:
from typing import TypedDict
class PizzaState(TypedDict):
toppings: list[str]
quantity: int
def add_cheese(state):
quantity = state["quantity"] + 1
return {"toppings": ["cheese"], "quantity": quantity}
from langgraph.graph import StateGraph
graph = StateGraph(PizzaState)
graph.add_node("cheese", add_cheese)
graph.set_entry_point("cheese")
graph.set_finish_point("cheese")
app = graph.compile()
initial_state = {"toppings": [], "quantity": 0}
app.invoke(initial_state)
def add_meat(state):
quantity = state["quantity"] + 1
return {"toppings": ["meat"], "quantity": quantity}
graph.add_node("meat", add_meat)
graph.add_edge("cheese", "meat")
graph.set_finish_point("meat")
from typing import TypedDict, Annotated
from operator import add
class PizzaState(TypedDict):
toppings: Annotated[list[str], add]
quantity: int