check if string contain only a-z/A-Z

[godsent]

Is where any way to check if string contains only a-z/A-Z, without writing an array with all possible letters and then looping it.

 

        
$available = array('a', 'b', 'c, 'd'); //write a-z

for ($i = 0; $i <= count($available); $i++) 
{
      $string = str_replace($available[$i], "", $string);
}

if ($string != "")
{
      print "Illegal character.";
} 

[laffin]

if(!preg_match('/^[a-z]+$/i',$string))
  echo 'Illegal characters';

[godsent]

can PHP see difference between capital letters (B and b), will this show capital letters as illegal?

[Alex]

A better alternative would be to use ctype_alpha, preg_match uses a lot more resources and it's unnecessary in this case. Example:

 

if(!ctype_alpha($string))
{
    // Contains illegal characters
}

 

[ot]In your example you did this:

$available = array('a', 'b', 'c', 'd'); //write a-z

If you actually needed to create an array of a-z you could do:

$arr = range('a', 'z');

[/ot]