I want to perform a case insensitive sub-string first appearance replacement.
I've tried this code :
$product_name_no_manufacturer = preg_replace("/$product_manufacturer/i","",$product_name, 1);
$product_name_no_manufacturer = trim($product_name_no_manufacturer);
but it doesn't work in some cases.
When -
$product_name = "3M 3M LAMP 027";
$product_manufacturer = "3m";
the result I get is :
"3M LAMP 027"
But when the parameters are different -
$product_name = "A+k A+k-SP-LAMP-027";
$product_manufacturer = "A+k";
the result I get is :
"A+k A+k-SP-LAMP-027"
Why preg_replace doesn't replace the first appearance of A+k?
+ is a special character in Regex ("match the preceding token once or more"), so you have to escape it. Whenever you insert a string into your Regex, escape it with preg_quote(), because it can contain special characters (leading to seemingly strange results as in this case).
$quoted = preg_quote($product_manufacturer, '/');
$product_name_no_manufacturer = preg_replace("/$quoted/i", "", $product_name, 1);
preg_quote() is what you are looking for.
Though
. \ + * ? [ ^ ] $ ( ) { } = ! < > | : -
are special characters in a pattern, you have to escape them first (A+k becomes A\+k).
Edit: Example here.
+ in regex have special means, you should escape it.
Actually, this can be solved without any regular expressions. There is a useful function strtr. So, you can use it like that:
$product_name_no_manufacturer
= strtr( $product_manufacturer, array( $product_name => '' ) );
This will be more faster than regexp and I think more convenient.