Why we have messed up values when we use enumerate to copy values from one array to another?

Question

This is my code with comments saying the output of the print functions:

def rotLeft(a, d):
    rotArray = a
    arraySize = len(a)

    print(a)#[1, 2, 3, 4, 5]

    for index, item in enumerate(a):
        print(index) # 0 1 2 3 4
        print(item) # 1 1 1 1 1
        rotArray[(index + 1) % arraySize] = item

    return rotArray

if I remove the last for instruction, we can retrieve the correct values. But if we maintan, somehow it does mess up with my original a array. Why this happen, and what is the good practice in this case?

`rotArray` and `a` are the same list. You didn't copy it, you just set another variable to the same object. — khelwood, May 01 '20 at 13:58
@schwobaseggl, it a variable to rotate the array, I will use when I fix this first part — Matheus Oliveira, May 01 '20 at 14:09

score 2 · Accepted Answer · answered May 01 '20 at 14:00

2

rotArray is referring to a, thus modifying it modifies a.

You can do this:

rotArray = a.copy()

answered May 01 '20 at 14:00

Vicrobot

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Why we have messed up values when we use enumerate to copy values from one array to another?

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