Which of the following is the correct way to create a RunnableLambda that doubles a number input?

easy📝 Syntax Q12 of 15

LangChain - Chains and LCEL

Which of the following is the correct way to create a RunnableLambda that doubles a number input?

ARunnableLambda(lambda x: x + 2)

BRunnableLambda(lambda x: x * 2)

CRunnableLambda(lambda x: x / 2)

DRunnableLambda(lambda x: x - 2)

Step-by-Step Solution

Solution:

Step 1: Identify the doubling function
Doubling means multiplying the input by 2, so the function should be lambda x: x * 2.
Step 2: Match with options
RunnableLambda(lambda x: x * 2) matches the doubling function exactly; others perform addition, division, or subtraction.
Final Answer:
RunnableLambda(lambda x: x * 2) -> Option B
Quick Check:
Doubling function uses multiplication by 2 = D [OK]

Quick Trick: Doubling means multiply input by 2 in lambda [OK]

Common Mistakes:

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