Issue with my code

MRAB python at mrabarnett.plus.com
Tue Feb 5 20:06:46 CET 2013


On 2013-02-05 18:38, maiden129 wrote:
> 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)
>          if t>1:
>              for k in range(1,t):
>                  s=s.remove(i)

The 'remove' method changes the list itself and then returns None, so
after executing this line the first time, s will be None.

>                  print(i, "occurs", t,"times.")
>
>          elif t==1:
>              print(i,"occurs 1 time.")
>      else: pass
>
> but it keeps showing this error:
>
>   t=s.count(i)
> AttributeError: 'NoneType' object has no attribute 'count'
>
> I wanted to show like this:
>
> Example:
>
> Enter a string: 3233456
>
> 3 occurs 3
> 2 occurs 1
> 4 occurs 1
> 5 occurs 1
> 6 occurs 1
>
You shouldn't add or remove items from a collection, such as a list,
over which you're iterating. Is it even necessary in this case? No.

Have a look at the Counter class in the collections module. That'll let
you eliminate most of your code! :-)



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