CODEWITHSUNDEEP
pythonpython-3.x
Keith
Keith

Reputation: 35

Weird python bug. Variable changes value without any modification

In the function "enText" changes its value even though I don't modify it.

e = 5 and n = 6. enText is an array of ints. I modify the values in the array after passing it to changeTxt. I then return changeTxt but for some reason enText ends up being modified as well.

No idea why.

#Function for encryption
    def encrypt(e, n, enText):

        #e=5 & n=6
        changeTxt = enText

        print(enText)
        #prints [18, 15, 2, 9, 14]

        for x in range(0, len(changeTxt)):

            #problem here!!!!!!!!
            tmp = changeTxt[x]**e
            tmp = tmp % n
            changeTxt[x] = tmp

        print(enText)
        #prints [0, 3, 2, 3, 2]

        return changeTxt

Upvotes: 2

Views: 215

Answers (1)

Ralf
Ralf

Reputation: 16505

Your line

changeTxt = enText

only copies the reference to the list, but both point to the same list. So changes to changeTxt will affect enText as well.

Instead try to clone the list like this:

changeTxt = enText[:]

or

changeTxt = list(enText)

Upvotes: 1

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