Free tool
Python list comprehension builder
Pick the shape (list / dict / set / generator), set the iterable + expression + optional filter, and see the comprehension AND the equivalent for-loop side by side. Then watch it actually execute against sample data — real Python via Skulpt, no server round-trip.
Sample input for testing:
nums = [1, -2, 3, -4, 5, -6, 7, -8, 9]. Change “Iterable” above to nums / words / users to load different samples, or type any name and the tool falls back to a generic [1, 2, 3, 4, 5].Comprehension
result = [x * 2 for x in nums if x > 0]
Equivalent for-loop
result = []
for x in nums:
if x > 0:
result.append(x * 2)Result on sample input
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