substr(),mb_substr()及mb_strcut函数用法与区别

<?php
$siteurl = 'www.111cn.net';
print_r (substr($siteurl,-6,2));exit;

<?php
echo mb_substr('这样一来我的字符串就不会有乱码^_^', 0, 7, 'utf-8');
?>

<?php
echo mb_strcut('这样一来我的字符串就不会有乱码^_^', 0, 7, 'utf-8');
?>

<?php
echo mb_substr('飞花院博客feihuayuan',0,9);
//返回: 飞花院

echo mb_substr('飞花院博客feihuayuan',0,9,'utf-8');
//则返回: 飞花院博客feih

mb_strcut('飞花院博客feihuayuan',0,9,'utf-8');
则返回:飞花院
?>

<?php
$str = '我是一串比较长的中文-';

echo "mb_substr:" . mb_substr($str, 0, 6, 'utf-8');

echo "<br>";

echo "mb_strcut:" . mb_strcut($str, 0, 6, 'utf-8');
?>

<a href="list.php?plate=辖区动态" charset="utf-8" target="main">[查看辖区动态]</a>

<a href="list.php?plate=<?php echo urlencode(“辖区动态");?>" charset="utf-8" target="main">[查看]</a>

$plate=urldecode($_GET['plate']);

<?php
echo '<a href="mycgi?foo=', urlencode($userinput), '">';
?>

<?php
$query_string = 'foo=' . urlencode($foo) . '&bar=' . urlencode($bar);
echo '<a href="mycgi?' . htmlentities($query_string) . '">';
?>

error_reporting(0);
 
// Report simple running errors
error_reporting(E_ERROR | E_WARNING | E_PARSE);
 
// Reporting E_NOTICE can be good too (to report uninitialized
// variables or catch variable name misspellings ...)
error_reporting(E_ERROR | E_WARNING | E_PARSE | E_NOTICE);
 
// Report all errors except E_NOTICE
// This is the default value set in php.ini
error_reporting(E_ALL ^ E_NOTICE);
 
// Report all PHP errors (bitwise 63 may be used in PHP 3)
error_reporting(E_ALL);
 
// Same as error_reporting(E_ALL);
ini_set('error_reporting', E_ALL);

$url = "http://www.111cn.net.net/welcome/";

$parts = parse_url($url);

print_r($parts);

array
(
    [scheme] => http
    [host] => www.111cn.net.net
    [path] => /welcome/
)

function getParams()
{
   $url = '/index.php?_p=index&_a=show&x=12&y=23';
  
   $refer_url = parse_url($url);
  
   $params = $refer_url['query'];
  
   $arr = array();
   if(!empty($params))
   {
       $paramsArr = explode('&',$params);
  
       foreach($paramsArr as $k=>$v)
       {
          $a = explode('=',$v);
          $arr[$a[0]] = $a[1];
       }
   }
   return $arr;
}

$arr = getParams();
print_r($arr);

<?php

header('Content-type: text/html; charset=utf-8');

$str = "dasdadsfsadASDSADS";

if (preg_match('/^[a-zA-Z]+$/',$str))
{
 echo $str."是字母";
}
else
{
 echo $str."不是字母";
}

?>

if(preg_match("/^d*$/",   "4312"))
{
echo   "全数字
";
}

if(preg_match("/^[a-z]*$/i",   "fdsFDfd"))
{
echo   "全字母
";
}

if(preg_match("/^[a-zd]*$/i",   "fd4fd34"))
{
echo   "有数字有字母
";
}