Peter Anderson wrote:
Hi! I am slowly teaching myself Python. I was reading David Beazley's
excellent book "Python - Essential Reference"; in particular about
variables. Let me quote:
"Python is a dynamically typed language in which names can represent
values of different types during the execution of a program. In fact the
names used in the program are really just labels for various quantities
and objects. The assignment operator simply creates an association
between a name and a value. This is different from C, for example, in
which a name (variable) represents a fixed size and location in memory..."
As an old mainframe programmer, I understand the way C does things with
variable but this text got me wondering how Python handles this
"association" between variable name and value at the lower level. Is it
like a fifo list?
If there is any Python guru that can help I would be most interested in
your thoughts.
Regards,
Peter
Names are pointers in Python that point to values in memory. Names are "bound"
to these values with assignment. Names are NOT buckets where you put values as
is the case (or thought process) in other languages. Example:
a = list(1,2,3)
b = a
Now a AND b point to the same list in memory
Note: if you wanted a COPY of the list you should do:
b = a[:]
Names can also point to functions, class instances, class methods or any other
object. Example:
def foo(arg):
print arg
bar = foo
Now you can call bar(arg) or foo(arg) and it will do exactly the same thing.
If you ever wrote assembler than you will begin to understand. varibles are
pointers to objects, not buckets were stuff is stored.
Hope this helps some.
-Larry
--
http://mail.python.org/mailman/listinfo/python-list
