[Tutor] Strings

[William Becerra]

Thank you guys

On Thu, Nov 6, 2014 at 3:39 AM, Dave Angel <davea at davea.name> wrote:

> William Becerra <wbecerra1 at gmail.com> Wrote in message:
> >
>
> have the following code:
> names = "John, Cindy, Peter"
> def find(str, ch, s):
>     index = 0
>     while index < len(str):
>         if s==1:
>             for char in names[:4]:
>                 if str[index] == ch:
>                     return index + 1
>                 index = index + 1
>         if s==2:
>             for char in names[6:11]:
>                 if str[index] == ch:
>                     return index + 1
>                 index = index + 1
>         if s==3:
>             for char in names[13:]:
>                 if str[index] == ch:
>                     return index + 1
>                 index = index + 1
>     return -1
> print find(names,"n", 2)
>
>
>
> and my problem is:
> I intend for the parameter s to tell the interpreter which name to
>  look at
> so that i get the index return value related to that name.
> for example:
> John and Cindy both have a letter 'n' but when I call the function
> with an s value of 2 I want it to return the index value of the
>  letter n in Cindy and not in John.
>
> Your most immediate problem is that you're using index to fetch
>  characters from the original string, and that's only reasonable
>  for John. You could make a slice of the original, and search that
>  slice. Or you could change the comparison to:
>    if char == ch:
>
> The loop could also be cleaner with enumerate.
>
> Your second big problem is that you've hard coded the sizes of the
>  first two names in the slice expressions. The magic [6:11] for
>  example  certainly doesn't belong inside the function.
>
>
> Third is your while loop makes no sense. Each of the if clauses
>  won't finish till you're done with the selected substring,  so
>  you might as well return right away. Drop that line entirely.
>
>
> Anyway, I say you're trying to do too much in the one function. If
>  possible change the data structure of names to eliminate one of
>  the two tasks, or write two functions, a few lines
>  each.
>
> I'd make
>   names = ["John", "Cindy", "Peter"]
> And start the function with
>   name = names [s-1]
>
> And now the task of the remainder of the function is to search a
>  name for a particular character.
>
> --
> DaveA
>
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