Usage examples of common string processing functions in PHP [conversion, escaping, interception, comparison, search, reversal, cutting]

';
echo '长度为: '.strlen($s);
echo '
';
//大小写
echo '首字母大写: '.Ucfirst($s);
echo '
';
echo '每个单词首字母大写: '.Ucwords($s);
echo '
';
echo '大写: '. Strtoupper($s);
echo '
';
echo '小写: '. Strtolower($s);
echo '
';
// 转义字符串函数,存入数据库前使用
echo 'addslashes(); stripslashes();';
$s1 = '"a"b';
echo '
';
echo addslashes($s1);
echo '
';
//截取
echo substr($s, 4, 4);
echo '
';
$s2 = "hello world";
$s3 = "test";
//比较,相等返回0
echo strcmp($s, $s2) == 0 ? "相等":"不等";
echo '
';
echo strcmp($s, $s3) == 0 ? "相等":"不等";
echo '
';
//查找
echo strpos($s, 'o');
echo '
';
echo strrpos($s, 'o');
//注意:如果查不到,则返回false == 0,所以要用"==="来检查if (XX === false);
echo '
';
//反转
echo strrev($s);
echo '
';
//切割
$arr = str_split($s);
$arr1 = str_split($s, 2);
$arr2 = explode(' ', $s);
var_dump($arr);
var_dump($arr1);
var_dump($arr2);
?>