Regex for SPSS field input

[BomberMan2K]

Hi guys,
I'm trying to build this little nifty form to get field names for SPSS software. The catch is it can only start with an alphachar (a-zA-z), continue with alphanumeric chars (a-z, A-Z, 0-9, _ - underscope) and can end with only alphanumeric char (not with an underscope).

suppose "val" is my input, I'm trying this regex:
if (val.match(/^([a-zA-Z]{1,}?|[a-zA-Z][a-zA-Z0-9_]+[a-zA-Z0-9])$/))

It works fine, but doesn't validate for "h1" for example (though it should). for "h_1" it does...
What is wrong with my expression here? Why doesn't it validate for "h1"?

Thank you,
Roman.

 

[darrellblackhawk]

Match 1st (alpha), 2nd through 5th (alphanum + _), 6th alpha

val = 'aad_3a_d2__a3'; // fails
val = 'aad_3a'; // pass
val = 'hh'; // pass
val = 'h1'; // pass

val.match(/^([a-zA-Z]{1}|[a-zA-Z][a-zA-Z0-9_]{1,4}[a-zA-Z0-9]$/);



Match 1st (alpha), 2nd through xth (alphanum + _), xth+1 alpha

val = 'aad_3a_d2__a3'; // pass
val = 'aad_3a'; // pass
val = 'h3asd3'; // pass
val = 'h1'; // pass

val.match(/^([a-zA-Z]{1}|[a-zA-Z][a-zA-Z0-9_]{1,}[a-zA-Z0-9])$/);

Darrell

 

[BomberMan2K]

Thanks Darrel,
But strangely enough - your regex doesn't work as well.

val = "h1" doesn't work. but "h11" does.

As I look at the regex it seems just fine... but still, something is wrong.

Would very appreciate more help


Roman.

 

[BomberMan2K]

Found the solution. Here it is: (seems to work 100%)

val.match(/^([a-zA-Z]{1,}|[a-zA-Z][a-zA-Z0-9_]{0,}[a-zA-Z0-9]{1,})$/)

 

[tsuji]

[tt]/^[a-zA-Z][a-zA-Z0-9_].*[a-zA-Z0-9]$/[/tt]
Or, unlikely needed for field names, this.
[tt]/^[a-zA-Z][a-zA-Z0-9_][\s\S]*[a-zA-Z0-9]$/[/tt]