preg_match problem

PHP
1

I am using

preg_match('[^a-zA-Z0-9_]', $testvar)

and when $testvar = “hgufy&&^%fff” it returns 0 and when $testvar = “kfjghfu” it returns 0.

What am I doing wrong. I would assume that in the first case it should return a positive result.

2

Go look at the preg_match documentation and you will see that regular expressions are contained inside a pair of forward slashes.

3

The reason why “hgufy&&^%fff” returns false is because is contains characters other then A-Z, 0-9 and _. The only real problem i see is no // declarations before [ and after ] which are required for [B]preg_match/B unlike [B]ereg/B which doesn’t require this.

Try the following as the + sign will check for repeated expressions within the string.

preg_match('/[^a-zA-Z0-9_]+/', $testvar)
4

Your’re missing something called “delimiters”. The first character inside a pattern is treated as a delimiter, which in your case is “[”; its corresponding closing delimiter would be “]” and your actual pattern becomes:

^a-zA-Z0-9_

Obviously wrong.

try adding a delimiter, such as “/” – though I prefer “@”:

preg_match('@[^a-zA-Z0-9_]@', $testvar);

You can shortenup your regexp like this:

preg_match('@\\W@', $testvar);
5

Thanks for the input, works great now. And Paul, I did look at the documentation several times and just missed it I guess.