Guys I want to know why the code below could not modify the list in reverse order. I am getting [8, 7, 6, 5, 5, 6, 7, 8] when I run the code. P assist

Question

x = [1, 2, 3, 4, 5, 6, 7, 8]

for num in range(len(x)):  
    x[num] = x[-(num + 1)]
print(x)

Guys I want to know why the code above could not modify the list in reverse order. I am getting [8, 7, 6, 5, 5, 6, 7, 8] when I run the code . Please kindly assist

You're overwriting the list as you're iterating over it. Print `x` in each iteration and you'll see. — AKX, Mar 26 '21 at 20:05
Please read [ask]. The title to your question is just awful. — John Coleman, Mar 26 '21 at 20:08
why don't you just give `x = x[::-1]` and see what you get? I have also posted the link to the duplicate question. See the link for more details — Joe Ferndz, Mar 26 '21 at 20:13

Joe Ferndz · Answer 1 · 2021-03-26T20:20:32.083

1

To reverse the string, all you need to do is mylist.reverse() or mylist[::-1]. For more details on this, please see Stack Overflow response from last year.

x = [1, 2, 3, 4, 5, 6, 7, 8]

x = x[::-1]

Original list:

[1, 2, 3, 4, 5, 6, 7, 8]

Updated list:

[8, 7, 6, 5, 4, 3, 2, 1]

edited Mar 26 '21 at 20:20

answered Mar 26 '21 at 20:14

Joe Ferndz

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will-hedges · Answer 2 · 2021-03-26T20:23:28.957

0

You are replacing existing values, and then looping back over them. What you want to use is the reverse method.

x = [1, 2, 3, 4, 5, 6, 7, 8]
x.reverse()
print(x)

edited Mar 26 '21 at 20:23

answered Mar 26 '21 at 20:08

will-hedges

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They want to reverse it, not sort. – bereal Mar 26 '21 at 20:10
@bereal ah I think you are correct. I couldn't tell after they used "for num in range(len(x))". Thanks – will-hedges Mar 26 '21 at 20:17

Guys I want to know why the code below could not modify the list in reverse order. I am getting [8, 7, 6, 5, 5, 6, 7, 8] when I run the code. P assist

2 Answers2