Best way to create a copy of a list

[Frank Millman]

Hi all

Assume a 2-dimensional list called 'table' - conceptually think of it
as rows and columns.

Assume I want to create a temporary copy of a row called 'row',
allowing me to modify the contents of 'row' without modifying the
contents of 'table'.

I used to fall into the newbie trap of 'row = table[23]', but I have
learned my lesson by now - changing 'row' also changes 'table'.

I have found two ways of doing it that seem to work.

1 - row = table[23][:]

2 - row = []
     row[:] = table[23]

Are these effectively identical, or is there a subtle distinction which
I should be aware of.

I did some timing tests, and 2 is quite a bit faster if 'row'
pre-exists and I just measure the second statement.

TIA

Frank Millman