php 基础函数

<?php//生成随机数 和 时间函数//echo rand();//echo "<br>";//echo rand(0,10);//echo time();//时间戳//2017-02-10 08:46:12date_default_timezone_set("Asia/Shanghai");//echo date("Y-m-d h:i:s");//默认转换当前时间//echo date("Y-m-d h:i:s",'1386688343');//echo strtotime("2013-12-10 11:12:23");//字符串的处理$str = 'Hello World!!!';//echo strlen($str);//$str1='Abc';//$str2='abc';//echo strcmp($str1,$str2);//echo strcasecmp($str1,$str2);echo strtoupper($str2);echo strtolower($str1);//$str = "a|B|c|d";//$str1 = explode("|",$str);//echo implode("&",$str1);//echo substr($str,1,3);//echo str_replace("|","&",$str);//echo substr_replace($str,"%",1,1);$str = "hello3 world4 ashdf223sdfa2323sd45454";//preg_match("//d/",$str,$str2);//preg_match_all("//d/",$str,$str3);//var_dump($str3);//$str4 = preg_replace("//d/", "数字", $str);//var_dump($str4);$str5 = preg_split("//d/",$str);var_dump($str5);