- print_r: documentation ( source)
<?php
$daysOfWeek = array(0=>'pon',1=>'wt',2=>'sr',3=>'czw',4=>'pt',5=>'sb',6=>'nd');
$converted = array();
foreach ($daysOfWeek as $key=>$checked) {
$converted[++$key] = $checked;
}
$converted[0] = $converted[7];
unset($converted[7]);
print_r($converted);