PHP | ctype_alnum() (Check for Alphanumeric)

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A ctype_alnum() function in PHP used to check all characters of given string/text are alphanumeric or not. If all characters are alphanumeric then return TRUE, otherwise return FALSE. Syntax:

 bool ctype_alnum ($text)

Parameters Used:

$text : It is a mandatory parameter which specifies the string.

Examples:

Input  : Geeks
Output : Yes
Explanation : String "Geeks" is alphanumeric.
              Note: Read Standard c local letter.
      
Input  : '%%%Contribute_article on GFG!!!'
Output : No
         
Explanation : String contains Special characters.

Note: Except string or digit, if we input anything then it will return FALSE.

Below programs illustrate the ctype_alnum() function. Program :1 Drive a code ctype_alnum()() function for better understand.

PHP

<?php
 
// PHP program to check given string is 
// all characters are alphanumeric
 
$string = 'zambiatek';
 
    if ( ctype_alnum($string))
        echo "Yes\n";
    else
        echo "No\n";
 
?>

Output:

Yes

Program: 2 Drive a code of ctype_alnum() function where input will be an array of string integers, string with special symbols.

PHP

<?php
// PHP program to check given string is 
// all characters are alphanumeric
 
$strings = array(
    'Geeks',
    'geek@gmail.com',
    '2018',
    'GFG2018',
    'a b c ',
    '@!$%^&*()|2018'
);
 
// Checking above given four strings 
// by used of  ctype_alnum() function .
foreach ($strings as $test) {
     
    if (ctype_alnum($test))
        echo "Yes\n";
    else
        echo "No\n";
     
}
 
?>