Question from a beginner

[Tuure Laurinolli]

Larry Bates wrote:

> Test1=vector(1,0,0)
> Test2=vector(1,0,0)
> 
> to get to "independent" instances of the vector object.

The copy function from module copy can also be used to create copies of 
objects.

> 
> All objects (that I'm aware of) in Python can be
> changed.  You can even overwrite Python's own
> objects.  People do it all the time when first
> learning.  Actually this comes in handy after you
> grow accustomed to it.

No, not all objects can be changed, but names can be rebound. For 
example strings and integers are immutable.

> 
> str="abc" 
> a=str(1)
> 
> and get an error because the str() function has been
> redefined to a string containing "abc".

The function hasn't been redefined, the name str has been changed to 
refer to a new object. Consider the following:

mystr = str
str = "foo"

and

mystr(1)
str(1)