Dev Nest Guide
pythonintermediate10 minutes

Predict the Output of a List Comprehension with Nested Conditions

Analyze a Python code snippet using nested list comprehensions with conditional statements and predict the final output list.

Challenge prompt

Consider the following Python code snippet: numbers = [1, 2, 3, 4, 5] result = [x * y for x in numbers if x % 2 == 0 for y in numbers if y > x] What is the output of the 'result' list after this code executes? Provide the exact list that will be printed if you run 'print(result)'.

Guidance

  • • Pay attention to the order of the nested for-loops inside the list comprehension.
  • • Understand the conditions applied to each loop variable before multiplying.
  • • Break down the comprehension step-by-step: first filter x, then filter y based on x, then multiply.

Hints

  • • x only iterates over even numbers in the 'numbers' list.
  • • For each valid x, y iterates over elements greater than x.
  • • Try listing out pairs (x, y) that satisfy both conditions before multiplying.

Starter code

numbers = [1, 2, 3, 4, 5]
result = [x * y for x in numbers if x % 2 == 0 for y in numbers if y > x]
print(result)

Expected output

[6, 8, 10, 20]

Core concepts

list comprehensionnested loopsconditional filteringPython iteration

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