[Solved] What happens if you call format on a PromptTemplate but omit a required variable?prompt = PromptTemplate(template="Hi {name}!") prompt.format() | LangChain

LangChain - Prompt Templates

What happens if you call format on a PromptTemplate but omit a required variable?

prompt = PromptTemplate(template="Hi {name}!")
prompt.format()

AReplaces {name} with an empty string

BRaises a KeyError because 'name' is missing

CReturns the template string unchanged

DAutomatically prompts for missing variables

Step-by-Step Solution

Solution:

Step 1: Understand format method requirements
The format method requires all placeholders to be provided as arguments.
Step 2: Predict behavior when variable is missing
Omitting a required variable causes a KeyError because the placeholder cannot be replaced.
Final Answer:
Raises a KeyError because 'name' is missing -> Option B
Quick Check:
Missing variable in format() causes KeyError [OK]

Quick Trick: Always provide all variables to format() [OK]

Common Mistakes:

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What happens if you call format on a PromptTemplate but omit a required variable?