The person who designed this database decided to make a multi-value column for "subjects" with each value written like an ordered list, i.e. "1. [subject] 2. [another subject] 3. [a third subject]" etc. I want to make an array of every subject used, so I need to split these values into distinct subjects.
$subjects = preg_split("[0-9]+\.\s", $subject);
When I run this, I get a Warning: preg_split() [function.preg-split]: Unknown modifier '+'.
What am I doing wrong?
You forgot the delimiters:
$subjects = preg_split("/[0-9]+\.\s/", $subject);
Also, slap that guy. Hard.
You're missing the pattern delimeters so php thinks [ ] are it.
Use e.g.
$subjects = preg_split("~[0-9]+\.s~", $subject);
In PHP, PCREs need delimiters. The most common one used is /, but you can also use another character:
preg_split('/[0-9]+\.\s/', $subject);
// ^ ^
You get this warning because PHP treats [] as delimiters.
This will give you an array like:
Array
(
[0] =>
[1] => [subject]
[2] => [another subject]
[3] => [a third subject]
)
so you'd have to remove the first item ( unset($subjects[0]) ).
Depending on the possible inputs, using preg_match_all might be better:
$str = "1. [subject] 2. [another subject] 3. [a third subject]";
preg_match_all('/\[([^\]]+)\]/', $str, $matches);
$subjects = $matches[1];
// or $subject = $matches[0]; if you want to include the brackets.
where $matches is
Array
(
[0] => Array
(
[0] => [subject]
[1] => [another subject]
[2] => [a third subject]
)
[1] => Array
(
[0] => subject
[1] => another subject
[2] => a third subject
)
)
You should write your regex with delimiters in order to avoid this error:
/[0-9]+\.\s/
