PHP字符串常用操作1

<?php
/*
    字符串相关操作
    strtoupper 将字符串转换为大写
    strtolower 将字符串转换为小写
    Ucfirst 如果开头是字母则大写
    ucwords 将每个单词的第一个字母大写
    explode 字符串分割
    implode 将一个数组合并成字符串
    substr 字符串截取
    strcmp 比较两个字符串,如果相等返回0,s1>s2返回1，小于返回-1，区分大小写
    strcasecmp 效果同上，但是不区分大小写
    strlen 得到字符串长度
*/
$str1 = "hello world";
echo strtoupper($str1);
echo '<hr>';
$str2 = "HELLO WOLRD";
echo strtolower($str2);
echo '<hr>';
$str3 = "h如果第一个字符时字母，则大写";
echo Ucfirst($str3);
echo '<hr>';
$str4 = "hello world china";
echo ucwords($str4);
echo '<hr>';
$str5 = "hello n'i";
$str5 = addslashes($str5);
echo $str5;
echo '<hr>';
$str6 = "hello,world,im,not";
$str6 = explode(",",$str6);
echo $str6[0];
echo $str6[1];
echo $str6[2];
echo "<hr>";
$str7 = array("one","two","three","for","five");
$str7 = implode("-",$str7);
echo $str7;
echo '<hr>';
$str8 = "abcdefghjk";
echo substr($str8,2)."<br>";
echo substr($str8,2,5)."<br>";
echo substr($str8,-2);
echo '<hr>';
$s1 = "hello";
$s2 = "hello";
$s = strcmp($s1,$s2);
echo $s;
echo "<hr>";
$s3 = "s";
echo strlen($s3);
?>