[FIXED] Why I am getting such strange behavior value for loop?

Issue

a = []
for i in range(10):
    a.append (i*i)

for a[i] in a:
    print(a[i])

For the above-mentioned code I am getting the output as follows:

0
1
4
9
16
25
36
49
64
64

I am not able to understand why 64 is getting repeated twice. If anyone knows the proper reason please explain me in detail.

Solution

With a suggestion that the loop should be like for item in a:, let's try to know the behavior for for a[i] in a:

a = []
for i in range(10):
    a.append (i*i)


print("Values before loop")
print(a, i)
for a[i] in a:
    print(a[i])
print("Values after loop")
print(a, i)

Values before loop
[0, 1, 4, 9, 16, 25, 36, 49, 64, 81] 9
0
1
4
9
16
25
36
49
64
64
Values after loop
[0, 1, 4, 9, 16, 25, 36, 49, 64, 64] 9

When you are iterating in above loop, i is always 9, so the iteration for a[i] in a assigns the subsequent values from a to a[i] i.e. a[9], hence, at second final iteration, the value a[9] becomes a[8], i.e. 64

Answered By - ThePyGuy