PHP: Add leading zeros to number and convert time 12 to 24 hours and vice versa

PHP:: Add leading zeros to number

$number = 3;

$invoice_no = sprintf(“%07d”, $number);

//output => 0000003

PHP convert time 12 to 24 hours and vice versa

// 24-hour time to 12-hour time
$time_in_12_hour_format  = DATE(“g:i a”, STRTOTIME(“23:15″));

// 12-hour time to 24-hour time
$time_in_24_hour_format  = DATE(“H:i”, STRTOTIME(“3:20 pm”));