How to avoid throwing an exceptions for a built-in function?

[k-five via Digitalmars-d-learn]

On Wednesday, 10 May 2017 at 13:12:46 UTC, Ivan Kazmenko wrote:
> On Wednesday, 10 May 2017 at 12:40:41 UTC, k-five wrote:
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>
> I assume that an empty string is a valid input then.
> The question is, what value do you want `index` to have when 
> the string is empty?
> Maybe the old value, or some constant?
> In any case, to better express your intent, you may write 
> something like:
>
>     if (user_apply[4] != "")
>     {
>         index = to !(int) (user_apply[4]);
>     }
>     else
>     {
>         index = ...;  // specify whatever your intent is
>     }
>
> This way, the code is self-documenting, and the program still 
> throws when `user_apply[4]` is neither empty nor an integer, 
> which may be the right thing to do in the long run.
>
> Ivan Kazmenko.
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Thanks, but I know about what are you saying. The user_apply[4] 
has so many possibilities and I cannot use if-else