On 16/6/2013 9:32 πμ, Denis McMahon wrote:
On Sat, 15 Jun 2013 19:18:53 +0300, Nick the Gr33k wrote:
In both situations we still have 2 memory units holding values, so hows
that different?
Consider that each named variable is a pointer to a memory location that
holds a value. This is one of the ways in that a typed compiled language
and an untyped scripted language may differ in their treatment of data
items (or variables).
Consider the following C and Python code:
C:
int a, b;
b = 6;
a = b;
In C, this places the numeric value 6 into the memory location identified
by the variable "b", then copies the value from the location pointed to
by "b" into the location pointed to by "a".
b is a pointer to a memory location containing the value 6
a is a pointer to another memory location also containing the value 6
Python:
b = 6
a = b
In Python, this first puts the value 6 in in a memory location and points
"b" at that memory location, then makes "a" point to the same memory
location as "b" points to.
b is a pointer to a memory location containing the value 6
a is a pointer to the same memory location
Do you understand the difference?
Yes and thank you for explaining in detail to me.
So Python economies(saves) system's memory. Good job Python!
There is no point having 2 variables point to 2 different memory
locations as C does since both of those memory locations are supposed to
contain the same value!
One thing that i want you guys to confirm to me:
a and b in both of the languages mentioned are pointers to memory
locations which hold a value.
A pointer = a variable that has as a value a memory address
a variable = a memory address that has as a value the actual value we
want to store.
But since pointer itself is a memory location that holds as a value the
address of another memory location(by definition) that in it's own turn
holds the actual value we want stored?
So the scheme would look like this in Python:
memory address = number 6
memory address = memory address value that stores number 6 (pointer a)
memory address = memory address value that stores number 6 (pointer b)
So having in mind the above.
The memory address that actually stores number 6 have no name at all and
the only way to access it's value is by printing the variables a or b?
Doesn't that memory address have a name itself?
if someone wants the memory address of the pointer's a or b, how can he
access it? in C it was somethign like &a and &b
And in Python internally shall i imagine two tables that has
associations of:
variable's_name <-> memory_address <-> actual value
And ALL 3 of them are actually bits(1s and 0s)
Is this how the thing works?
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What is now proved was at first only imagined!
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