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Re: Issue with my code

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On Tue, 5 Feb 2013 10:38:55 -0800 (PST), maiden129
<sengokubasarafever@gmail.com> declaimed the following in
gmane.comp.python.general:

> Hi,
> 
> I'm trying to create this program that counts the occurrences of each digit in a string which the user have to enter.
> 
> Here is my code:
> 
> s=input("Enter a string, eg(4856w23874): ")
> s=list(s)
> 
> checkS=['0','1','2','3','4','5','6','7','8','9']
> 
> for i in s:
>     if i in checkS:
>         t=s.count(i)

	Let's see... for each character in the input, see if that character
is in the check list, and if it is, then reverse and count the
occurences in the input string. (Oh, that's after you converted the
input to a list of single characters)


>         if t>1:
>             for k in range(1,t):
>                 s=s.remove(i)
>                 print(i, "occurs", t,"times.")


	Oh Oh.... Besides the fact that .remove() does its work in-place
(and doesn't return a value -- hence the "s=" is binding None to s), you
are trying to modify the string that you are looping over... And that is
a no-no -- it will cause you to skip over items.

-=-=-=-=-=-
>>> s = list("123456789")
>>> for c in s:
... 	if c == "3":
... 		s.remove(c)
... 		print "c: %s\tREMOVED" % (c,)
... 	else:
... 		print "c: %s\ts: %s" % (c, s)
... 		
c: 1	s: ['1', '2', '3', '4', '5', '6', '7', '8', '9']
c: 2	s: ['1', '2', '3', '4', '5', '6', '7', '8', '9']
c: 3	REMOVED
c: 5	s: ['1', '2', '4', '5', '6', '7', '8', '9']
c: 6	s: ['1', '2', '4', '5', '6', '7', '8', '9']
c: 7	s: ['1', '2', '4', '5', '6', '7', '8', '9']
c: 8	s: ['1', '2', '4', '5', '6', '7', '8', '9']
c: 9	s: ['1', '2', '4', '5', '6', '7', '8', '9']
>>> 
-=-=-=-=-=-

	Note how there is no line for c=4. When you remove the "3", all the
rest shift left to fill in -- but the next round of the loop is going to
"increment" to the character after the position that "3" was at... That
is now the "5".

	Rather than working from the input list, why not turn it around...

-=-=-=-=-=-
>>> inpt = "4856w2304874"
>>> digits = "0123456789"
>>> for d in digits:
... 	o = inpt.count(d)
... 	if o:
... 		print "%s occurs %s times" % (d, o)
... 
0 occurs 1 times
2 occurs 1 times
3 occurs 1 times
4 occurs 3 times
5 occurs 1 times
6 occurs 1 times
7 occurs 1 times
8 occurs 2 times
>>> 
-=-=-=-=-=-
-- 
	Wulfraed                 Dennis Lee Bieber         AF6VN
        wlfraed@ix.netcom.com    HTTP://wlfraed.home.netcom.com/

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Issue with my code maiden129 <sengokubasarafever@gmail.com> - 2013-02-05 10:38 -0800
  Re: Issue with my code maiden129 <sengokubasarafever@gmail.com> - 2013-02-05 10:43 -0800
  Re: Issue with my code marduk <marduk@python.net> - 2013-02-05 13:56 -0500
    Re: Issue with my code maiden129 <sengokubasarafever@gmail.com> - 2013-02-05 11:20 -0800
      Re: Issue with my code Dave Angel <davea@davea.name> - 2013-02-05 14:43 -0500
        Re: Issue with my code maiden129 <sengokubasarafever@gmail.com> - 2013-02-05 12:19 -0800
        Re: Issue with my code maiden129 <sengokubasarafever@gmail.com> - 2013-02-05 12:19 -0800
          Re: Issue with my code darnold <darnold992000@yahoo.com> - 2013-02-05 13:37 -0800
            Re: Issue with my code marduk <marduk@python.net> - 2013-02-05 17:05 -0500
              Re: Issue with my code darnold <darnold992000@yahoo.com> - 2013-02-05 14:25 -0800
    Re: Issue with my code maiden129 <sengokubasarafever@gmail.com> - 2013-02-05 11:20 -0800
  Re: Issue with my code MRAB <python@mrabarnett.plus.com> - 2013-02-05 19:06 +0000
  Re: Issue with my code Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-02-05 17:20 -0500
  Re: Issue with my code Terry Reedy <tjreedy@udel.edu> - 2013-02-05 19:06 -0500
  Re: Issue with my code rusi <rustompmody@gmail.com> - 2013-02-05 22:29 -0800
    Re: Issue with my code rusi <rustompmody@gmail.com> - 2013-02-05 22:32 -0800

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