Questions / Quant development, Python correctness
Capture a loop variable
In Python, what is sum(f() for f in fs)?
fs = [lambda: i for i in range(3)]Answer it in the app It's free. You get hints, a second try if you miss, and a follow-up question.
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Answer: 6 value
- All three lambdas look up the same loop variable after the loop, when i=2. The sum is 2+2+2=6.
Interview shortcut. Closures bind late: every lambda sees the final i = 2.
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