How to str_split string from right to left?

Question

Let's say i have a number 10000 and i want to split it by 2 characters from right to left resulting in array something like this [0] => 1,[1] => 00,[2] => 00. Is it somehow possible with str_split($var, 2); ?

Answer 1

There must be easier ways, but you can use something like:

array_map("strrev", array_reverse(str_split(strrev(10000), 2)));

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[0] => 1
[1] => 00
[2] => 00

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1. strrev() - Reverse a string
2. str_split() - Convert a string to an array
3. array_reverse() - Return an array with elements in reverse order
4. array_map() - Applies the callback to the elements of the given arrays

Answer 2

You can use preg_split to check positions where the number of digits until the end is even.

$result = preg_split('~\B(?=(..)+$)~', '10000');

\B the non-word boundary, prevents to match the start of the string. (The non-word boundary only matches between two digits)
(?=(..)+$) is a lookahead that checks if the position is followed by an even number of characters.

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Otherwise you can add a leading 0 when the string length is odd and remove it in the first item:

$str = '10000';

if ( strlen($str) & 1 ) {
    $res = str_split("0$str", 2);
    $res[0] = (int)$res[0];
} else {
    $res = str_split($str, 2);
}

print_r($res);

or shorter using the ternary operator:

$result = str_split( strlen($str) & 1 ? "0$str" : $str, 2);
$result[0] = (int)$result[0];