[Python-ideas] Proposal to change List Sequence Repetition (*) so it is not useless for Mutable Objects

[Greg Ewing]

> On 31.05.2016 07:27, Matthew Tanous wrote:
>>
>>arr = [[True] * 5] * 5
>>
>>This does not create a matrix-like arrangement of the immutable truth
>>variable, but instead creates a list of 5 references to the same list

I think this would be better addressed by an extension
to list comprehensions, e.g.

   arr = [[True times 5] times 5]

where

   [x times n]

would be equivalent to

   [x for i in range(n)]

Since this would evaluate x afresh for each elment, it
would avoid all the thorny issues involved in trying to
automatically deep-copy arbitrary objects.

-- 
Greg