You want to run three independent tasks taskX, taskY, and taskZ in parallel and combine their results into a single string separated by commas. Which code correctly does this?

hard📝 Application Q15 of 15

LangChain - Chains and LCEL

You want to run three independent tasks taskX, taskY, and taskZ in parallel and combine their results into a single string separated by commas. Which code correctly does this?

Aparallel = RunnableParallel(taskX, taskY, taskZ) results = parallel.invoke() combined = ','.join(results) print(combined)

Bparallel = RunnableParallel({"taskX": taskX, "taskY": taskY, "taskZ": taskZ}) results = parallel.invoke() combined = ','.join(results.values()) print(combined)

Cresults = [taskX(), taskY(), taskZ()] combined = ','.join(results) print(combined)

Dparallel = RunnableParallel([taskX, taskY, taskZ]) combined = parallel.invoke().join(',') print(combined)

Step-by-Step Solution

Solution:

Step 1: Create RunnableParallel with dictionary of tasks
parallel = RunnableParallel({"taskX": taskX, "taskY": taskY, "taskZ": taskZ}) results = parallel.invoke() combined = ','.join(results.values()) print(combined) correctly passes tasks as a dictionary to RunnableParallel.
Step 2: Invoke and join results properly
This calls invoke() to get dict results, then joins the values with commas correctly.
Step 3: Check other options for errors
parallel = RunnableParallel(taskX, taskY, taskZ) results = parallel.invoke() combined = ','.join(results) print(combined) passes tasks incorrectly as positional; C runs tasks sequentially; D uses invalid list and misuses join.
Final Answer:
Using RunnableParallel({"taskX": taskX, "taskY": taskY, "taskZ": taskZ}) and ','.join(results.values()) -> Option B
Quick Check:
Dict tasks + invoke + join values = correct [OK]

Quick Trick: Pass tasks as dict, invoke, then ','.join(results.values()) [OK]

Common Mistakes:

Passing tasks without dictionary syntax
Calling join() on the wrong object
Running tasks sequentially instead of parallel

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You want to run three independent tasks taskX, taskY, and taskZ in parallel and combine their results into a single string separated by commas. Which code correctly does this?

Step 1: Create RunnableParallel with dictionary of tasks

Step 2: Invoke and join results properly

Step 3: Check other options for errors

Final Answer:

Quick Check:

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