LangChain Knowledge Check | Dataford Interview Questions

Tell me about LangChain.

Implement a minimal LangChain-style runnable pipeline that composes prompt formatting, model invocation, and output parsing. The function receives ordered step definitions and initial variables, then returns the final string. A prompt step formats its template with the current dictionary, a model step formats a deterministic response template using {input}, and a parser step applies either strip or first_line.

Constraints

1 <= len(steps) <= 20
steps contains prompt, model, and parser steps in a valid execution order
Prompt templates reference keys present in the current dictionary
Model response templates use the {input} placeholder
Parser mode is either strip or first_line
All values are strings except the initial variables dictionary

Function Signature

def run_chain(steps, variables):

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Problem

Tell me about LangChain.

Constraints

1 <= len(steps) <= 20
steps contains prompt, model, and parser steps in a valid execution order
Prompt templates reference keys present in the current dictionary
Model response templates use the {input} placeholder
Parser mode is either strip or first_line
All values are strings except the initial variables dictionary

Function Signature

def run_chain(steps, variables):

Your question is LangChain Knowledge Check. Start with the requirements in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.