[Tutor] doubt in a program

[Nitin Madhok]

Vinod,

First time it loops, 
newstring = ‘’
oldstring = ‘Newton’
char = ‘N’
char + newstring = ‘N’ + ‘’ = ‘N’

Second time it loops,
newstring = ‘N’
oldstring = ‘Newton’
char = ‘e’
char + newstring = ‘e’ +’N’ = ‘eN’

Third time it loops,
newstring = ‘eN’
oldstring = ‘Newton’
char = ‘w’
char + newstring = ‘w’ +’eN’ = ‘weN’

Fourth time it loops,
newstring = ‘weN’
oldstring = ‘Newton’
char = ‘t’
char + newstring = ‘t’ +’weN’ = ‘tweN’

Fifth time it loops,
newstring = ‘tweN’
oldstring = ‘Newton’
char = ‘o’
char + newstring = ‘o’ +’tweN’ = ‘otweN’

Sixth/Final time it loops:
newstring = ‘otweN’
oldstring = ‘Newton’
char = ‘n’
char + newstring = ‘n’ +’otweN’ = ‘notweN’

newstring after loop finishes will be ‘notweN’ which is the reverse of ‘Newton’

Let me know if that explanation helps you understand it better. There are built in functions to reverse a string that are more efficient than this approach that you should be using to reverse a string.

--

Thanks,
Nitin Madhok
Clemson University

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> On Jan 29, 2018, at 1:42 AM, vinod bhaskaran <bhaskaran.vinod at gmail.com> wrote:
> 
> Hi,
> 
> I am a new beginner in programming.
> I saw a code (given below) to reverse  string.
> 
> newstring = ''
> oldstring = 'Newton'
> for char in oldstring:
>   newstring = char + newstring
> print(newstring)
> 
> 
> 
> Could someone explain how it is traversing to get the string reversed?
> 
> As the new character is adding the char in the new string but how is it
> getting reversed without any line giving the char number to be traversed in
> reverse order.
> 
> Thanks,
> Vinod
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