Regular Expressions (Specifically preg_split() PHP)

Question

I'm listing out some dates in my PHP application which results in something like the following:

April2016May2016June2016 etc.

I'm trying to use preg_split to format them like this:

array('April 2016', 'May 2016', 'June 2016')

I used an online Regular Expression editor to determine how to detect for 4 consecutive numbers and here's how far I've gotten:

Note: I am also removing all white space - ideally this would be better if it only removed white space if there were more than 2 spaces i.e. hello world would not be altered but hello world would.

preg_split('/\d\d\d\d/g', preg_replace('!\s+!', '', $sidebar_contents));

Using the above, I get an error suggesting that the g identifier is not valid assuming because it's not preg_match_all - removing the g result in the following:

Thanks for any help!

Answer 1

Here is a way to achieve what you want with 1 call to preg_match_all and using an array_map after:

preg_match_all('~(\p{L}+)(\d+)~', "April2016May2016June2016", $m);
$result = array_map(function($k, $v) { return $k . " " . $v; }, $m[1], $m[2]);
print_r($result);

See the regex demo and an IDEONE demo.

The pattern means:

• (\p{L}+) - match and capture into Group 1 (will be accessible after matching via $m[1]) one or more letters
• (\d+) - match and capture into Group 2 (will be accessible after matching via $m[2]) one or more digits.

With array_map, we just join the values from Group 1 and 2 with a space.

Alternative: fill out the resulting array inside a preg_replace_callback (just one pass!):

$result = array();
preg_replace_callback('~(\p{L}+)(\d+)~', function($m) use (&$result) {
    array_push($result, $m[1] . " " . $m[2]);
}, "April2016May2016June2016");
print_r($result);

See the IDEONE demo.