reg exp question

[bpw89]

Hi,
I am trying to make sure that a string contains only letters, and no other characters.

I am using:

function checkletters($string) {
if (!preg_match($string, "^([a-z]|[A-Z])*$")) {
return true;
} else {
return false;
}
}

I am getting this error:

"Warning: preg_match() [function.preg-match]: Delimiter must not be alphanumeric or backslash in /path/to/file.php on line 47"

Line 47 is the one that contains "if (!preg_match($string, "^([a-z]|[A-Z])*$")) {", so I know there is something wrong with my reg exp.

Question: am I doing this the 'right way' or is there a string function that I should use instead?

THANKS

 

[jpadie]

function checkletters($input){
 //function returns true if no non-letters present in $input
 $input = trim($input); //get rid of extraneous spaces
 $pattern = '/^[a-zA-Z]/';
 if ( false === preg_match($input, $pattern)) {
   //no matches found so ok
   return true;
  } else {
   return false; 
}

 

[bpw89]

Thanks for your suggestion.

As a rule of thumb, I usually think of a solution right after I give up and post a question. In this case, I used:

function checkletters($string) {
$bad = eregi_replace("([a-zA-Z]+)","",$string);
if($bad == "") {
return false;
} else {
return true;
}
}

The reason for returning true if there is a problem and false if it is OK, is so I can use syntax like this in the main script:

if(checkletters($string)) {
$error="invalid input";
}

 

[jpadie]

I would have thought that my code would be quite a bit faster (PCRE is natively faster than POSIX)

function checkletters($input){
  return (preg_match(trim($input).  '/^[a-zA-Z]/')) ? TRUE :FALSE;
}