Questions / Quant development, Python correctness
A shallow copy shares children
After this Python code, what is len(a[0])?
a = [[1], [2]]
b = a.copy()
b[0].append(9)Answer it in the app It's free. You get hints, a second try if you miss, and a follow-up question.
Show the answer and worked solution
Answer: 2 length
- The outer list is copied, but its nested list is shared. Appending through b[0] also changes a[0].
Interview shortcut. .copy() is shallow: inner lists are shared.
In the app this has a follow-up where one thing about the setup changes. Try the follow-up.