Bucle for python

Question

hello guys this is my first post, there will be someone to help me understand the python for loop especially with this code

A = [1,2,3,4,1]
for n in A:
A[n]=0
print(A)

oputput: [0, 0, 3, 0, 1]

why the output is that is not supposed to be pure zeros pls help me understand!! and thanks

Answer 1

It's like this
for loop runs
1--> n=1
A[1] = 0
A = [1, 0, 3, 4, 1]
now 2nd element is 0
2--> n = 0
A[0] = 0
A = [0, 0, 3, 4, 1]
3--> n= 3
A[3] = 0
A = [0, 0, 3, 0, 1]
4--> n = 0
already value is 0
so list makes no difference.
5--> n = 1
already value is 0

Answer 2

PaI2tition list[list[4]] is out of range & not list[4]
list[4] = 8
so list[list[4]] = list[8] = error
please go through the explanation again ...
take ur time to understand...

Answer 3

PaI2tition
list[3] = 4
list[4] = 8
therefore
list[list[3]] = list[4] = 8

when u put 4 inside
list[list[4]]
list[4] = 8
list[8] = error, since the index is out of range...
list contains 6 elements so highest possible index can be 5...
index start from 0

Answer 4

https://code.sololearn.com/ctv6UjztxeFg/?ref=app

Answer 5

n = A[0] = 1
[1,0,3,4,1]

n = A[1] = 0
[0,0,3,4,1]

n = A[2] = 3
[0,0,3,0,1]

n = A[3] = 0
[0,0,3,0,1]

n = A[4] = 1
[0,0,3,0,1]

Please ask if it's still unclear.

Oh, 🌛DT🌜 was faster.

Answer 6

sorry bro, iam not a native english so its hard for me to understand and thanks for all :)

Answer 7

ty all guys i have another question why this code print 8
and why if I put the index 4 gives me error, if u can explain i will be grateful :) , sorry guys for my nab questions but i really want to learn,

list = [1,1,2,4,8,10]
print(list[list[3]])

output: 8

Answer 8

but look this DT index 4 is out of range
https://code.sololearn.com/cZF71IQGO7lp/?ref=app