[Solved] Identify the issue in this LangChain code snippet:from langchain import PromptTemplate prompt = PromptTemplate(template="Welcome, {user}!") print(prompt.format(username="Bob")) | LangChain

LangChain - Fundamentals

Identify the issue in this LangChain code snippet:

from langchain import PromptTemplate
prompt = PromptTemplate(template="Welcome, {user}!")
print(prompt.format(username="Bob"))

AThe template string is missing required curly braces

BPromptTemplate cannot be imported from langchain

CThe input variable name in format() does not match the template variable

DThe print statement syntax is incorrect

Step-by-Step Solution

Solution:

Step 1: Check template variable
The template uses '{user}' as the variable.
Step 2: Check format() argument
The code calls prompt.format(username="Bob"), which uses 'username' instead of 'user'.
Step 3: Identify mismatch
This mismatch causes a KeyError because 'user' is expected but 'username' is provided.
Final Answer:
The input variable name in format() does not match the template variable -> Option C
Quick Check:
Variable names must match exactly [OK]

Quick Trick: Template and format variable names must match [OK]

Common Mistakes:

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