[Tutor] Why does loop duplicate?

[Mark Lawrence]

On 16/12/2015 19:37, Ken Hammer wrote:
> Intent is to print "Jack, Kack, ...." with "O" and "Q" delivering a longer suffix.  Instead, I get the printout shown with duplicates and a second deviation with "O" and "Q" as shown.
> Why?

That's what you've told the code to do :)

>
> prefixes = 'JKLMNOPQ'   ###FAILS WITH REPEATS

### OH NO IT DOESN'T - nothing personal but it's pantomine season in the 
UK :)

> suffix = 'ack'
> suffixb= 'uack'
>
> for letter in prefixes:
>      if letter == "O":
>          print letter + suffixb
>      if letter == "Q":
>          print letter + suffixb
>      else:
>          print letter + suffix
>

You test for "O", but then follow with a test for "Q" and an else 
clause.  You could write :-

elif letter == "Q"

but the cleanest way of doing this is:-

for letter in prefixes:
     if letter in ("O", "Q"):
         print letter + suffixb
     else:
         print letter + suffix

-- 
My fellow Pythonistas, ask not what our language can do for you, ask
what you can do for our language.

Mark Lawrence