Doug Stell a écrit : > I am having a problem with the corruption of a list. It occurs only > the first time that I call a function and never happens on subsequent > calls. Any suggestions would be appreciated. > > I call the function, passing in a list as the input data. The function > must manipulate and operate on a copy of that list's data, without > altering the list in the calling routine. > > def myFunc(listA): > listB = listA > work on & modify listB > return(listB)
return is a statement, not a function. Please remove these useless (and possibly harmful) parens. > The first time this function touches listB, listA is corrupted. It's not. It's just that you did *not* copy listA - you just made listB reference the same object. > > I concluded that it appears that listB is still pointing at elements > of listA It's even worse : both names listA and listB are pointing to the exact same object. listA = ['A', 'B', 'C'] listB = listA assert listA is listB > and I need to force Python to reassign those pointers s/pointers/references/ > to > point to copies of listA's elements. copy.deepcopy() is your friend then. -- http://mail.python.org/mailman/listinfo/python-list
