正则表达式：获取括号外的内容

Question

I'm using PHP and I have text like:

first [abc] middle [xyz] last

I need to get what's inside and outside of the brackets. Searching in StackOverflow I found a pattern to get what's inside:

preg_match_all('/\[.*?\]/', $m, $s)

Now I'd like to know the pattern to get what's outside.

Regards!

Answer 1

You can use preg_split for this as:

$input ='first [abc] middle [xyz] last';
$arr = preg_split('/\[.*?\]/',$input);
print_r($arr);

Output:

Array
(
    [0] => first 
    [1] =>  middle 
    [2] =>  last
)

This allows some surrounding spaces in the output. If you don't want them you can use:

$arr = preg_split('/\s*\[.*?\]\s*/',$input);

---

preg_split splits the string based on a pattern. The pattern here is [ followed by anything followed by ]. The regex to match anything is .*. Also [ and ] are regex meta char used for char class. Since we want to match them literally we need to escape them to get \[.*\]. .* is by default greedy and will try to match as much as possible. In this case it will match abc] middle [xyz. To avoid this we make it non greedy by appending it with a ? to give \[.*?\]. Since our def of anything here actually means anything other than ] we can also use \[[^]]*?\]

EDIT:

If you want to extract words that are both inside and outside the [], you can use:

$arr = preg_split('/\[|\]/',$input);

which split the string on a [ or a ]