Frank Millman wrote: > 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.
you could use list() row = list(table[23]) The effect is the same, but it's nicer to read. See also the copy module. -- http://mail.python.org/mailman/listinfo/python-list
