Web Hosting Talk : Web Hosting Main Forums : Programming Discussion : PHP: String validation

[mylinear]

How do I validate whether a string meets the following criteria.
1. Must be 6 to 12 characters in length
2. Must consists of only a to z with no spaces etc

I was using:
$string = "abcdef";
$pattern = "/[a-z]{6,12}/";
preg_match($pattern, $sring);
// returns true

But I found that it would also return true with other strings such as:
$string = " abcdef xyz";

Do I need to include the 3rd array parameter in preg_match and use the resulting array element to do further checking on the match? Or should I not be using preg_match to do this sort of validation?

[mylinear]

Upon further testing, this appears to work.

$pattern = "/^[a-z]{6,12}$/";

But I'm still not sure whether it is the correct way to do this.

[ChristsLittleFlock]

Yes, you need to include the ^ and $; otherwise, as long as 6 consecutive letters in the string match the pattern, it's happy, even if other characters do not match. The ^ tells it, though, that the pattern must be first in the string, and $ tells it that the pattern must also be last.

[mylinear]

Thanks to Hostultrix-Brandon for the pointer.

I came across some tutorials and examples on the following site that others may find helpful.

http://www.regularexpressions.info/