[Solved] You want to parse a nested Pydantic model output using PydanticOutputParser. Given:class Address(BaseModel): city: str zip_code: str class Person(BaseModel): name: str address:... | LangChain

LangChain - Output Parsers

You want to parse a nested Pydantic model output using PydanticOutputParser. Given:

class Address(BaseModel):
    city: str
    zip_code: str

class Person(BaseModel):
    name: str
    address: Address

parser = PydanticOutputParser(model=Person)
output = '{"name": "Eve", "address": {"city": "NY", "zip_code": "10001"}}'
result = parser.parse(output)
print(result.address.city)

What will be printed?

ANY

B{'city': 'NY', 'zip_code': '10001'}

CAn error because nested models are not supported

DNone

Step-by-Step Solution

Solution:

Step 1: Understand nested model parsing
PydanticOutputParser supports nested models and parses nested JSON accordingly.
Step 2: Access nested field value
result.address.city accesses the city string 'NY' inside the nested Address model.
Final Answer:
NY -> Option A
Quick Check:
Nested models parse correctly and fields accessible [OK]

Quick Trick: Nested Pydantic models parse nested JSON objects correctly [OK]

Common Mistakes:

Thinking nested models cause errors
Expecting dict instead of nested model instance
Assuming nested fields are None

Master "Output Parsers" in LangChain

9 interactive learning modes - each teaches the same concept differently

Learn Why Deep Visual Try Challenge Project Recall Perf

More LangChain Quizzes

You want to parse a nested Pydantic model output using PydanticOutputParser. Given:

Step 1: Understand nested model parsing

Step 2: Access nested field value

Final Answer:

Quick Check:

Want More Practice?