- str_repeat: documentation ( source)
- strtr: documentation ( source)
- var_export: documentation ( source)
<?php
$atcode = '11F5796B61690196';
$sub1 = [
'0' => '2',
'1' => '3',
'2' => '0',
'3' => '1',
'4' => '6',
'5' => '7',
'7' => '5',
'8' => 'A',
'9' => 'B',
'A' => '8',
'B' => '9',
'C' => 'E',
'D' => 'F',
'E' => 'C',
'F' => 'D'
];
var_export(
str_repeat(
strtr($atcode[14], $sub1) . $atcode[15],
2
)
);