I am no Python guru - just an ordinary user. There is nothing "scary" about this. There are (many) situations where this is actually *desirable* but of course there are (many) situations where this is an unwelcomed side-effect.
In situations where I don't want this to happen, I simply pass down the list as an non-mutable object (like converting the list to a tuple). It took me a little bit of getting used to this concept as well: everything is either a mutable object, or a non-mutable object. I just have to throw away trying to use concept of "pointers" in Python. SpreadTooThin wrote: > I'm really worried that python may is doing some things I wasn't > expecting... but lets see... > > if I pass a list to a function def fn(myList): > > and in that function I modify an element in the list, then does the > callers list get modied as well. > > def fn(list): > list[1] = 0 > > myList = [1, 2, 3] > print myList > fn(myList) > print myList > > >>> [1,2,3] > >>> [1,0,3] > > How can I avoid this? In this case this is a really simplified example > but the effects are the same... > How do I specify or create deep copies of objects that may contain > other objects that may contain other > object that may contain other objects.... -- http://mail.python.org/mailman/listinfo/python-list
