include dot(.) and hyphen(-) in a regex

Question

 if(preg_match(\'/[^a-z\\-0-9]/i\', $value))

    {
    echo \"\";
}

how

Answer 1

The hyphen doesn't need to be escaped if it's the first or last in the character class.
The dot also doesn't need to escaped when used inside a character class [] i.e.:

/[^a-z.0-9-]/i

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NOTES:

Apart from the above, the meta characters that also need to be escaped inside a character class are:

^ (negation)
- (range)
] (end of the class)
\ (escape char)