php实现的DateDiff和DateAdd时间函数代码分享

function DateAdd($part,$number,$date)
{
$date_array = getdate(strtotime($date));
$hor = $date_array["hours"];
$min = $date_array["minutes"];
$sec = $date_array["seconds"];
$mon = $date_array["mon"];
$day = $date_array["mday"];
$yar = $date_array["year"];
switch($part)
{
case "y": $yar += $number; break;
case "q": $mon += ($number 3); break;
case "m": $mon += $number; break;
case "w": $day += ($number 7); break;
case "d": $day += $number; break;
case "h": $hor += $number; break;
case "n": $min += $number; break;
case "s": $sec += $number; break;
}
return date("Y-m-d H:i:s",mktime($hor,$min,$sec,$mon,$day,$yar));
}

Function DateAdd($part,$n,$date)
{
switch($part)
{
case "y": $val = date("Y-m-d H:i:s",strtotime($date ." +$n year")); break;
case "m": $val = date("Y-m-d H:i:s",strtotime($date ." +$n month")); break;
case "w": $val = date("Y-m-d H:i:s",strtotime($date ." +$n week")); break;
case "d": $val = date("Y-m-d H:i:s",strtotime($date ." +$n day")); break;
case "h": $val = date("Y-m-d H:i:s",strtotime($date ." +$n hour")); break;
case "n": $val = date("Y-m-d H:i:s",strtotime($date ." +$n minute")); break;
case "s": $val = date("Y-m-d H:i:s",strtotime($date ." +$n second")); break;
}
return $val;
}