Use preg_split for all special characters

Question

I want to split a String everytime a special character is found.

I did this :

preg_split("[\\W]", $str);

But this will still allow underscore (and maybe more?)

Is it possible to just say allow a-z A-Z and digits and split on anything that is not one of these?

Answer 1

You have just answered your question:

preg_split('~[^a-z0-9]~i', $str);

See this regex demo

The [^a-z0-9] negated character class matches any character other than a-z (and A-Z due to the i modifier) and other than a digit (defined with 0-9).

Another way is with using POSIX [:alnum:] character class inside a negated character class:

'~[^[:alnum:]]~'

See regex demo

Note that it is easier to use single char regex delimiters rather than paired ones, my favorite being ~. It is rarely used in regex patterns, and thus I do not have to escape too much in my patterns.