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PHP | ctype_alnum() Function

PHP ctype_alnum() Function

Hello folks! welcome back to a new edition of our tutorial on PHP. In this tutorial guide, we are going to be studying about the PHP ctype_alnum() Function.

The built-in ctype_alnum() Function checks if all the characters in the given string, text, are alphanumeric. In the standard C locale letters are just [A-Z, a-z] and the function is equivalent to preg_match('/^[a-z0-9]+$/iD', $text).


Following below is the syntax to use this function -

ctype_alnum ( $text );

Parameter Details

Sr.NoParameters & Description


The tested string.

Return Value

This built-in function returns TRUE if every character in the given text is either a letter or digit, otherwise FALSE.


Try out the below example -

   $strings = array('hello', 'foo!#$bar');
   foreach ($strings as $example) {
      if (ctype_alnum($example)) {
         echo "$example consists of all letters or digits. \n";
      }else {
         echo "$example does not have all letters or digits. \n";


When the above code is executed, it will produce the following result -

hello consists of all letters or digits.
foo!#$bar does not have all letters or digits.

Alright guys! This is where we are going to be rounding up for this tutorial post. In our next tutorial, we are going to be discussing about the PHP ctype_alpha() Function.

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