String as Number

// https://stackoverflow.com/questions/64676862/how-to-encode-decode-string-to-decimal-number-in-php
// As suggested in the comments, you can put it into hex and that into its numeric representation.

$list = array(
    "string0",
    "string1",
    "string2",
    "string3",
    "string4",
    "string5",
);

function numberEncode($value){
    return hexdec(bin2hex($value));
}

function numberDecode($value){
    return hex2bin(dechex($value));
}

$list2 = array();
foreach($list as $value){
    $list2[] = numberEncode($value);
}

print_r($list2);

$list3 = array();
foreach($list2 as $value){
    $list3[] = numberDecode($value);
}

print_r($list3);

/*
Array
(
    [0] => 32497657065662256
    [1] => 32497657065662257
    [2] => 32497657065662258
    [3] => 32497657065662259
    [4] => 32497657065662260
    [5] => 32497657065662261
)
Array
(
    [0] => string0
    [1] => string1
    [2] => string2
    [3] => string3
    [4] => string4
    [5] => string5
)
*/