CODEWITHSUNDEEP
phpregexstringvalidation
Leysam Rosario
Leysam Rosario

Reputation: 369

check if there are non-letters or non-numbers in the string

How can I detect a non number or non letter on a string?

KY4R5EHCN5W476XXO5ER - return true

KY4R5EHCN5W472X**@**O5ER - return false

I know the answer is to use a regular expression, I just don't know how to do it. I suck at regular expressions. Any help will be appreciated.

Thanks!

Upvotes: -1

Views: 1735

Answers (6)

Toto
Toto

Reputation: 91385

Use this regex to be unicode compatible:

/^[\p{L}\p{N}]+$/u

Upvotes: 1

Fanis Hatzidakis
Fanis Hatzidakis

Reputation: 5340

ctype_alnum() will be quite faster than a regular expression in detecting if a string is purely alpha-numeric (letters and numbers). 

$str1 = 'KY4R5EHCN5W476XXO5ER';
$str2 = 'KY4R5EHCN5W472X*@*O5ER' ;

foreach (array($str1, $str2) as $str){ 

    if (ctype_alnum($str)) {
        echo "$str is alphanumeric\n" ;
    }
    else {
        echo "$str is not just alphanumeric\n";
    }
}

However, be sure to play with the regular expressions given here because it's a useful skill to have, especially if you later decide you also need to check for other characters like dashes. You will find The Regex Coach very useful when experimenting with them.

$str = 'KY4R5EHCN5W476XXO5ER' ;
$ut = microtime(true) ;

for ($i = 0 ; $i < 100000; $i++) {
    $res = ctype_alnum($str) ;
}

$utCtype = microtime(true) ;

for ($i = 0 ; $i < 100000; $i++) {
    $res = preg_match('/[a-z0-9]/i', $str) ;
} 

$utEnd = microtime(true) ;

$utDiffCtype = $utCtype - $ut ;
$utDiffPreg = $utEnd - $utCtype;

echo "ctype: $utDiffCtype, preg: $utDiffPreg" ;

Upvotes: 1

nickb
nickb

Reputation: 59699

if (preg_match('/[^a-z0-9]/i', $subject)) {
    // Invalid characters
} else {
    // Only letters and numbers
}

Upvotes: 4

Eliasdx
Eliasdx

Reputation: 2180

(preg_match('/^[A-Z0-9]+$/', $string) == 0)

change to a-zA-Z0-9 if you want to include lowercase characters

this should return true if the string contains only A-Z and 0-9.

or

(preg_match('/[^A-Z0-9]/', $string) != 0)

should do pretty much the same.

Upvotes: 0

Aurelio De Rosa
Aurelio De Rosa

Reputation: 22152

You can use this:

if (preg_match('/^([a-z0-9]+)$/iu', $string))
{
   // all alpha and digits
}
else
{
   // not all alpha and digits
}

Upvotes: 0

Marc B
Marc B

Reputation: 360572

if (preg_match('/[^A-Z0-9]/', $string)) {
    ... some char other than A-Z, 0-9 detected
}

Upvotes: 4

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