list vs tuple

[deadmeat]

> Have you used other languages before coming to Python?  I would
> think it would be confusing to people who were used to languages
> that have a reference/value inconsistency.  Python is totally
> consistent (everything is a object, all names refer to objects).

No it's not.  I come from a Pascal background, the behaviour noted in the
parent is what would happen if two pointers were made equal.  To copy the
contents from one variable to another, a ^ is used to refer to the structure
at the pointer, not the pointer itself.

Python does not do that

>>> a = 1
>>> b = a
>>> a = 5
>>> b
1

>>> a = [1,2,3]
>>> b = a
>>> b[1] = 999
>>> b
[1, 999, 3]

It's dependant on datatype, which most people would think as inconsistant.

Example 2 is the same for function arguments, pass all lists to functions
with a [:] on the end to ensure your function doesn't modify your list
without the parent code knowing about it.