Python/More about Variables at master · GudiVaraprasad/Python · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
let us check what there behind this...
when you assign a=5, the object gets created in the memory. This has certain address

a=5
id(a)
output is 1507379184    ------> this is the address of the object

s='python'                              // It is also valid for strings
id(s)
output is 23235456
suppose ....
a=8
b=a
id(a)
output is 1507379232
id(b)
output is 1507379232            ------> you can observe that the address of a and b are the same that means in simple words,
                                        a and b have same data so they are pointing towards same object located in the memory....
                                        that where python is more memory efficient
 you can also know address of this by,
 id(8)
output is 1507379232

now change the value of a,,
a=7
id(a)
output is 1507379216
id(b)                                    // you can observe that the address of a and b are different as b has same id before assigned
1507379232                                  to a (b=a)...now the value of a is changed so address changed....but b willnot vary as the
                                            assigned value for b is still old a (b=8)
lets change the value of b
b=3
id(b)
output is 1507379152
now the memory is used for 10 and nothing is assigned to it...but it got stored in the memory
this is the concept of "Garbage collection" in python

some universal constants like PI are used in python and these values cannot be channged....
PI=3.14
PI
output is 3.14

type(PI)                             // You can find the data type of any object using < type(<variable>) >
output is <class 'float'>
type(s)
output is <class 'str'>


Quiz Question :  How is set different from list in python ..??
Answer :
set is collection of unique elements, like in list if you repeat something i.e some number like 12 then it is repeated again,
but in sets if you write 12 number 2 times then it will display only once, so this is 1st one. 2nd one is set is working on
concept of hash, where list not working on concept of hash! 3rd one is in sets index number is not working, because sets can't
maintain sequence, but list maintain sequence, eo index number is working in list! So these are some of difference between
set and list!