"Nick L" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] > I've hit a brick wall on something that I'm guessing is pretty simple but > it's driving me nuts. I noticed that with python lists, generally when > you > make a copy of a list (ie, List1 = List2)
Python is not C, etc. Assigning a name to an object *never* makes a copy. Assigning a second name creates an alias. Aliases are problems in any language that allows them (which C does also, via pointers). Consider Nick_PythonLearner = Nick_L > List1 just becomes a reference to List2 Ditto for the two Nick names, but better said, both names refer to the same person (or list). > and any modifications done to List1 affects List2. and ditto for a person with more than one name -- which is almost everyone in the modern world (Nick, Mr. L, etc). > Ok I can live with this Good. Name confusion is everywhere. > but I want to make a completely seperate [sic] copy not attached to the > original in anyway. So then I used this method. List1 = List2[:] For a shallow (one level) copy, List1=list(List2) is now prefered. For a deep (complete, all-level) copy, follow Kern's advice: copy.deepcopy. Terry J. Reedy -- http://mail.python.org/mailman/listinfo/python-list
