20191101php日期练习

<?php
echo abs(-23);
echo "<hr/>";
echo date("t");
echo "<hr/>";
echo mt_rand();
echo "<hr/>";
echo floor(pi());
echo "<hr/>";
echo ceil(pi());
echo "<hr/>";

$str=date("Y-m-d H:i:s",time());//标准的日期
echo $str;
date_default_timezone_set("PRC");//北京时间
echo "<br/>";
$str=date("Y-m-d H:i:s",time());
echo $str;

echo "<br/>";
echo "<br/>";

$sj=date("z",mktime("0","0","0","09","01","2019"));
echo "开学到现在的天数";
echo (date("z")-$sj)."天";
echo "<br/>";
print_r(getdate());//是一个数组的形式

echo "<br/>";
echo strtotime("now");//将当前时间转换为时间戳.
echo strtotime("2019-5-26 14:30:52");
//'+' '-'
echo date("Y-m-d h:i:s",strtotime("+1 day"));

echo "<hr />";

echo date("Y-m-d H:i:s",strtotime("-1 year 5 hours"));

echo "<hr />";
//last
echo date("Y-m-d H:i:s",strtotime("last monday"));

echo "<hr />";
//next
echo date("Y-m-d H:i:s",strtotime("next Friday"));
echo "<hr />";
echo date("Y年m月t w z");
?>