php how to escape a string for preg_match?

Question

I'am trying to pass a string

  preg_replace('/'.preg_quote($my_str).'/i', '', $string);

but I get an error

preg_replace(): Unknown modifier '\'

is there any other solutions to escape those backslashes?

You have to pass regexp delimiter (/) as 2nd parameter for preg_quote — hindmost
– hindmost, Commented Apr 12, 2014 at 13:10
What is the regular expression you're passing into preg_quote? You may need to add a delimiter. — Jordan Doyle
– Jordan Doyle, Commented Apr 12, 2014 at 13:11

Nambi · Accepted Answer · 2014-04-12 15:23:34Z

2

Pass the delimiter to the second argument of the preg_quote

echo preg_replace('/'.preg_quote("$my_str",'~').'/i', '',$string );
                                            ^

answered Apr 12, 2014 at 13:17

Nambi

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Comments

Sabuj Hassan · Accepted Answer · 2014-04-12 13:17:41Z

0

Your $my_str contains / character in it which you are using as regex delimiter. So you have two solutions,

One, replace the delimiter / into anything else which doesn't contain in the variable. For example ~

preg_replace('~'.preg_quote($my_str).'~i', '', $string);
              ^                       ^

Second solution, replace all the / with \/ from $my_str after preg_quote

$my_str = str_replace('/', '\/', preg_quote($my_str));
$some_str = preg_replace('/'.$my_str.'/i', '', $string);

answered Apr 12, 2014 at 13:17

Sabuj Hassan

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