mrk...@gmail.com wrote:
Baolong zhen wrote:
less list creation.
At the cost of doing this at each 'flatten' call:
if res is None:
res = []
The number of situations of executing above code is the same as the
number of list creations (once for each 'flatten' call, obviously).
Is list creation really more costly than above?
Probably not. I wrote a small test program using a list several levels
deep, each list containing 5 sublists at each level and finally just a
list of numbers. Flattening 1000 times took about 3.9 seconds for the
one creating a list at each level, and 3.2 for the one not creating the
list at each level.
Brian Vanderburg II
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