PHP 日期格式化（获取上月第一天、最后一天等）

1.获取上个月第一天及最后一天.
echo date('Y-m-01', strtotime('-1 month'));
echo "<br/>";
echo date('Y-m-t', strtotime('-1 month'));
echo "<br/>";
2.获取当月第一天及最后一天.
$BeginDate=date('Y-m-01', strtotime(date("Y-m-d")));
echo $BeginDate;
echo "<br/>";
echo date('Y-m-d', strtotime("$BeginDate +1 month -1 day"));
echo "<br/>";
3.获取当天年份、月份、日及天数.
echo " 本月共有:".date("t")."天";
echo " 当前年份".date('Y');
echo " 当前月份".date('m');
echo " 当前几号".date('d');
echo "<br/>";
4.使用函数及数组来获取当月第一天及最后一天,比较实用
function getthemonth($date)
{
$firstday = date('Y-m-01', strtotime($date));
$lastday = date('Y-m-d', strtotime("$firstday +1 month -1 day"));
return array($firstday,$lastday);
}
$today = date("Y-m-d");
$day=getthemonth($today);
echo "当月的第一天: ".$day[0]." 当月的最后一天: ".$day[1];
echo "<br/>";

<?php
echo date("Ymd",strtotime("now")), "\n";
echo date("Ymd",strtotime("-1 week Monday")), "\n";
echo date("Ymd",strtotime("-1 week Sunday")), "\n";
echo date("Ymd",strtotime("+0 week Monday")), "\n";
echo date("Ymd",strtotime("+0 week Sunday")), "\n";

echo "*********第几个月:";
echo date('n');
echo "*********本周周几:";
echo date("w");
echo "*********本月天数:";
echo date("t");
echo "*********";

echo '<br>上周起始时间:<br>';
echo date("Y-m-d H:i:s",mktime(0, 0 , 0,date("m"),date("d")-date("w")+1-7,date("Y"))),"\n";
echo date("Y-m-d H:i:s",mktime(23,59,59,date("m"),date("d")-date("w")+7-7,date("Y"))),"\n";
echo '<br>本周起始时间:<br>';
echo date("Y-m-d H:i:s",mktime(0, 0 , 0,date("m"),date("d")-date("w")+1,date("Y"))),"\n";
echo date("Y-m-d H:i:s",mktime(23,59,59,date("m"),date("d")-date("w")+7,date("Y"))),"\n";

//从第几周找出该周的开始日期和结束日期
$dayNumber = date('W') * 7;
$weekDayNumber = date("w", mktime(0, 0, 0, 1, $dayNumber, date("Y")));//当前周的第几天
$startNumber = $dayNumber - $weekDayNumber;
echo date("Y-m-d", mktime(0, 0, 0, 1, $startNumber + 1, date("Y")));//开始日期
echo date("Y-m-d", mktime(0, 0, 0, 1, $startNumber + 7, date("Y")));//结束日期

echo '<br>上月起始时间:<br>';
echo date("Y-m-d H:i:s",mktime(0, 0 , 0,date("m")-1,1,date("Y"))),"\n";
echo date("Y-m-d H:i:s",mktime(23,59,59,date("m") ,0,date("Y"))),"\n";
echo '<br>本月起始时间:<br>';
echo date("Y-m-d H:i:s",mktime(0, 0 , 0,date("m"),1,date("Y"))),"\n";
echo date("Y-m-d H:i:s",mktime(23,59,59,date("m"),date("t"),date("Y"))),"\n";

$season = ceil((date('n'))/3);//当月是第几季度
echo '<br>本季度起始时间:<br>';
echo date('Y-m-d H:i:s', mktime(0, 0, 0,$season*3-3+1,1,date('Y'))),"\n";
echo date('Y-m-d H:i:s', mktime(23,59,59,$season*3,date('t',mktime(0, 0 , 0,$season*3,1,date("Y"))),date('Y'))),"\n";

$season = ceil((date('n'))/3)-1;//上季度是第几季度
echo '<br>上季度起始时间:<br>';
echo date('Y-m-d H:i:s', mktime(0, 0, 0,$season*3-3+1,1,date('Y'))),"\n";
echo date('Y-m-d H:i:s', mktime(23,59,59,$season*3,date('t',mktime(0, 0 , 0,$season*3,1,date("Y"))),date('Y'))),"\n";
?>