[SOLVED] Need help with user name validation

[feha]

:rtfm:/^[a-z0-9]+(?:[-][a-z0-9]+)*$/

 

I need help with this ...

it should let the user name type  :

aa10-233-22  etc and it seams to work ok

 

what i need is how to add to this regex the min max limit in total  ex {2,50}

so the user name will be min 2 and max 50 chers including hypens ...

 

Sorry i'm not that good in regex ...

 

The reg-ex should:

validate:

xx-xxx-xxxx-xx-xx  (x: any length and alphanumeric lower case ...)

should not validate:

xx--xx---xx  etc

should not begin and end with - (hypen)

and should have min-max limit ...

 

for any help thank you in advance

 

[.josh]

function validateString($string) {
  if (strlen($s) > 1 && strlen($s) < 51) {
    if (preg_match('~^[a-z0-9]+-?[a-z0-9]+$~i',$s))
      return true;
  }
  return false;
} 

[feha]

Hi Cryon

 

Thank you, this should work ok ...

 

how about something like:

/^[a-z0-9]+-?[a-z0-9]+$/  using {2,50} ?

can this be done ?

 

Thank You

 

[feha]

also the best working reg-ex for this i got:

 

/^[a-z0-9]+([-]?[a-z0-9])*$/

 

this works ok as:

aaa-100-aa-1000  etc ...

 

 

[.josh]

you can add range to the regex but it's more optimal to use the strlen condition first.  strlen is a lot faster than using {2,50} in a pattern so it's better to pre-qualify the string like that, instead of putting it in the regex.  If it doesn't validate on the strlen condition, you also save php the work of having to go through the rest of the regex. 

 

Regex is a powerful tool, but wherever possible, you should always use built-in functions. 

[feha]

you can add range to the regex but it's more optimal to use the strlen condition first.  strlen is a lot faster than using {2,50} in a pattern so it's better to pre-qualify the string like that, instead of putting it in the regex.  If it doesn't validate on the strlen condition, you also save php the work of having to go through the rest of the regex. 

 

Regex is a powerful tool, but wherever possible, you should always use built-in functions. 

 

Thanks Cryon

U'r right, but some times it is needed just in single line (as i need it now )

The problem is i can't get it work if i try {2,50} (i don't know where to place it on /^[a-z0-9]+([-]?[a-z0-9])*$/ , as i get errors) I'm not an expert in regex ...

 

Thank you for your help

 

[.josh]

give me a legit reason why you need a one line regex solution.

[feha]

give me a legit reason why you need a one line regex solution.

I'm using an IDE Code Generator, so it has the validation field for reg-ex,

i can't put there any function except the reg-ex it self.

 

 

 

[.josh]

fair enough. This should work:

 

/^[a-zA-Z0-9](?:[a-zA-Z0-9]|(?!--)-){0,48}[a-zA-Z0-9]$/

[.josh]

er..I guess your OP said all lowercase so remove all the A-Z in there

[feha]

fair enough. This should work:

 

/^[a-zA-Z0-9](?:[a-zA-Z0-9]|(?!--)-){0,48}[a-zA-Z0-9]$/

 

Thank you very much, it works great :-)

I guess if i wan min 3 chars i need to change {0,48} to {0,47} :-)

[.josh]

no actually you would need to do {1,48}

 

The first character class and last character class account for the minimum of 2.  {0,48} will match nothing up to 48 characters.  so to make it a minimum of 3, you'd up the minimum range, not lower the max.

[feha]

no actually you would need to do {1,48}

 

The first character class and last character class account for the minimum of 2.  {0,48} will match nothing up to 48 characters.  so to make it a minimum of 3, you'd up the minimum range, not lower the max.

Great, this was very nice solution, thank you again for your great help.

I'll need to learn more about RegEx :-)