Remove all characters with ascii codes 32 - 47 and some more from string

Question

I want to remove all characters with ascii codes 32 - 47 and some more from string. Exactly !"#$%&'()*+,-./\~.

I tried:

$string = preg_replace('/\s\!\"\#\$\%\&\'\(\)\*\+\,\-\.\/\\~/', '', $string);

But it returned false. What am I doing wrong? Thanks.

You should really read about [**character classes**](https://www.regular-expressions.info/charclass.html). See https://stackoverflow.com/questions/1545751/how-to-back-reference-inner-selections-in-a-regular-expression/1553171#1553171, https://stackoverflow.com/questions/9801630/what-is-the-difference-between-square-brackets-and-parentheses-in-a-regex — Wiktor Stribiżew, Oct 26 '17 at 21:12
I read this http://www.regular-expressions.info/unicode.html. So I was close to find it :) — Legionar, Oct 26 '17 at 21:12

AbraCadaver · Accepted Answer · 2017-10-26T21:30:15.060

1

To use the characters just include them in a character class:

$string = preg_replace(':[\s!"#$%&\'()*+,-./\\\~]:', '', $string);

Or use ASCII hexadecimal for the range and characters:

[\x20-\x2f\x5c\x7e]

Or use the actual characters in a range as long as you start with the first (space) and end with the last / in the range and then add the rest:

[ -/\\\~]

edited Oct 26 '17 at 21:30

answered Oct 26 '17 at 21:13

AbraCadaver

`'` should be escaped with ``\``. Also what, if I also want to remove `~`? – Legionar Oct 26 '17 at 21:16
@Legionar Chars that are used as regex delimiters must be escaped inside the pattern. – Wiktor Stribiżew Oct 26 '17 at 21:19
@AbraCadaver its not working - `ERROR: missing terminating ] for character class at offset 21` - tested on https://www.functions-online.com/preg_replace.html – Legionar Oct 26 '17 at 21:20
@AbraCadaver I am answering OP top comment. – Wiktor Stribiżew Oct 26 '17 at 21:20
Now its ok. Thanks. Also I added there ``\~``, as I edited question. – Legionar Oct 26 '17 at 21:23
"we need 4 \" -- no you don't, since `'[\\\]' === '[\\\\]'` is `true` (the value being `[\\]`). – salathe Oct 26 '17 at 21:25
@AbraCadaver as I showed above, it doesn't matter; 3 slashes or 4 slashes, the value ends up with 2 slashes. – salathe Oct 26 '17 at 21:29

1 Answers1