Add multiple LangGraph examples including basic agents, chatbots, conditional edges, checkpointers, tool calls, and human-in-the-loop approval processes. Update .gitignore to include local environment files.

07_command.py

@@ -0,0 +1,51 @@
+from typing import Literal, TypedDict
+
+from langgraph.graph import END, START, StateGraph
+from langgraph.types import Command
+
+
+class State(TypedDict):
+    number: int
+    result: str
+
+
+def check_number(
+    state: State,
+) -> Command[Literal["positive", "negative"]]:
+    if state["number"] >= 0:
+        return Command(
+            update={"result": "这是非负数"},
+            goto="positive",
+        )
+
+    return Command(
+        update={"result": "这是负数"},
+        goto="negative",
+    )
+
+
+def positive(state: State):
+    print(state["result"])
+    return {}
+
+
+def negative(state: State):
+    print(state["result"])
+    return {}
+
+
+builder = StateGraph(State)
+builder.add_node("check", check_number)
+builder.add_node("positive", positive)
+builder.add_node("negative", negative)
+
+builder.add_edge(START, "check")
+builder.add_edge("positive", END)
+builder.add_edge("negative", END)
+
+graph = builder.compile()
+
+graph.invoke({
+    "number": -5,
+    "result": "",
+})