PHP preg_match for only numbers and letters, no special characters

Question

I don't want preg_match_all ... because the form field only allows for numbers and letters... just wondering what the right syntax is...

Nothing fancy ... just need to know the right syntax for a preg_match statement that looks for only numbers and letters. Something like

preg_match('/^([^.]+)\.([^.]+)\.com$/', $unit)

But that doesn't look for numbers too....

Can you give more detail about what you're trying to achieve here? Maybe an example. Are you trying to match all alphanum or just the first one, or something else? — whoughton, Apr 05 '11 at 14:17

score 32 · Accepted Answer · answered Apr 05 '11 at 14:20

If you just want to ensure a string contains only alphanumeric characters. A-Z, a-z, 0-9 you don't need to use regular expressions.

Use ctype_alnum()

Example from the documentation:

<?php
$strings = array('AbCd1zyZ9', 'foo!#$bar');
foreach ($strings as $testcase) {
    if (ctype_alnum($testcase)) {
        echo "The string $testcase consists of all letters or digits.\n";
    } else {
        echo "The string $testcase does not consist of all letters or digits.\n";
    }
}
?>

The above example will output:

The string AbCd1zyZ9 consists of all letters or digits.
The string foo!#$bar does not consist of all letters or digits.

I did not know about `ctype_alnum`. +1 – gen_Eric Apr 05 '11 at 14:21 — gen_Eric, Apr 05 '11 at 14:21

score 16 · Answer 2 · edited Nov 28 '13 at 22:32

16

if(preg_match("/[A-Za-z0-9]+/", $content) == TRUE){

} else {

}

edited Nov 28 '13 at 22:32

Matt

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answered Apr 05 '11 at 14:20

Vish

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It won't let me edit it because it's not enough characters, but ("/(A-Za-z0-9]+/", $content) should be ("/[A-Za-z0-9]+/", $content). Notice the [ instead of ( – emilyk Apr 03 '13 at 17:54
1

@emilyk tried two times to process an edit to fix this but got denied every time. So we'll stick with the not working version then. – bicycle Jun 10 '13 at 08:54

score 5 · Answer 3 · edited Apr 05 '11 at 14:19

5

If you want to match more than 1, then you'll need to, however, provide us with some code and we can help better.

although, in the meantime:

preg_match("/([a-zA-Z0-9])/", $formContent, $result);
print_r($result);

:)

edited Apr 05 '11 at 14:19

KingCrunch

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answered Apr 05 '11 at 14:18

Richard Dickinson

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PHP preg_match for only numbers and letters, no special characters

3 Answers3

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