preg_split in php to split string at the point which is preceded by digit and is followed by letters or blank space

Question

In order to split my string at the point which is preceded by digit and is followed by letters as:

 $str = '12jan';

I have used

$arr = preg_split('/(?<=[0-9])(?=[a-z]+)/i',$str);  

It works file and gives the desired output. I want to update it so that it gives the same output for strings like.

$str='12 jan';
$str='12    jan';
$str='12/jan';
$str='12//jan';
$str='12/jan';
$str='12*/jan';
$str='12*//jan';

The code should work for any strings given above so that at the end of the day I have a array like

Array
(
    [0] => 12
    [1] => jan
)

Any help will be appreciated.

Answer 1

This may be optimized if you answer my question in the comment.

Pattern: ~(?<=[0-9])[*/ ]*(?=[a-z]+)~i

Demo

The above will match zero or more *, / and/or space characters.

---

On your input strings, this will be just as accurate and faster:

Pattern: ~\d+\K[^a-z]*~i
or: ~\d+\K[*/ ]*~ (no case-sensitive pattern modifier is necessary)

Demo

The above will match zero or more non-alphabetical characters immediately following the leading digit(s).

---

And of course preg_split's cousins can also do nicely:

Here is a battery of PHP Demos.

$strings=['12jan','12 jan','12    jan','12/jan','12//jan','12/jan','12*/jan','12*//jan'];

foreach($strings as $string){
    var_export(preg_split('~(?<=[0-9])[*/ ]*(?=[a-z]+)~i',$string));
    echo "\n";
    var_export(preg_split('~\d+\K[*/ ]*~',$string));
    echo "\n";
    var_export(preg_match('~(\d+)[/* ]*([a-z]+)~i',$string,$out)?array_slice($out,1):'fail');
    echo "\n";
    var_export(preg_match('~(\d+)[/* ]*(.+)~',$string,$out)?array_slice($out,1):'fail');
    echo "\n";
    var_export(preg_match_all('~\d+|[a-z]+~i',$string,$out)?$out[0]:'fail');
    echo "\n---\n";
}

All methods provide the same output.