help with preg_match

mufka · Mar 7, 2008

I'm using the following to validate a form field

Code:

!preg_match("/^[-a-z\,\.\:\'\s]+$/i",$_POST["subject"])

I cannot see why the form fails to validate if there is an ' in the submission.

jpadie · Mar 7, 2008

are you trying to say that the field must only contain a comma, dash, full stop, single quote, colon and alphabet (and space)

if so, i'm not sure why your escaping so much stuff. i'd only look to escape the dash. i think that's probably the issue.

Code:

$pattern = "/^[a-z \-,.:']+$/i";

you should also test for 0 rather than false (to be precise). preg_match returns an integer corresponding to the number of matches.

Code:

if ( preg_match($pattern, $subject) === 0 ){
 echo 'invalid form field';
}

mufka · Mar 7, 2008

Code:

$pattern = "/^[a-z \-,.:']+$/i";

doesn't work either. It still won't allow an ' in the field.

jpadie · Mar 7, 2008

i can't help you then. on my machines this code

Code:

<?php
$pattern = "/^[a-z \-,.:']+$/i";
$subject[] = "I am a test string";
$subject[] = "I am a John O'Connor";
$subject[] = "I am a test with illegal [characters]";
foreach($subject as $s){
	if(preg_match($pattern, $s) === 0 ){
		echo "string not matched";
	} else {
		echo "string matched";
	}
	echo "<br/>";
}
?>

results in this

Code:

string matched
string matched
string not matched

which is as expected.

mufka · Mar 7, 2008

Using $subject instead of $_POST["subject"] fixed it. I also changed to testing for 0 while I was at it.

jpadie · Mar 7, 2008

glad to hear it.

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help with preg_match

mufka

ISP

jpadie

Technical User

mufka

ISP

jpadie

Technical User

mufka

ISP

jpadie

Technical User

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