问数之间的循环循环(范围)

EN

$arr = array(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31);

    foreach( $arr as $key => $value ) {
        if ( ( $key % 5 ) <= 2 ) echo "<b>" . $value  . "</b>"; 
        else echo $value; 

        echo "<br />";
    }

$days = range(1,31);
$i = 3; // consecutive bolded days
$j = 2; // consecutive not bolded days between the bolded
$str ="";
for($k=0;$k<end($days);){
    $str .= "<b>" . implode("</b> <b>", array_slice($days, $k,$i)) ."</b> " . implode(" ", array_slice($days, $k+$i, $j)). " ";
    $k=$k+$i+$j;
}
echo $str;

for ($i = 0; $i < 31; $i++) {
    if ($i%5 == 1 || $i%5 == 2 || $i%5 == 3 ) {
        echo "<strong>" . $i . "</strong>";
    } else {
        echo $i;
    }
}