php中str_replace替换实例讲解-php开发

这篇文章主要介绍了php中str_replace替换实例讲解内容，有需要的朋友们可以学习参考下。

在对于字符串的替换上，我们已经学过了不少的方法。但在做练习题的时候，我们会对多个字符串进行替换。从方法的实用性来说，str_replace就非常适合处理多个字符串的替换问题。下面我们就php中str_replace的概念、语法、参数、返回值进行讲解，然后带来替换的实例分享。

1、概念

str_replace() 函数以其他字符替换字符串中的一些字符（区分大小写）。

该函数区分大小写。请使用 str_ireplace() 函数执行不区分大小写的搜索。

2、语法


str_replace(find,replace,string,count)

3、参数

Find、replace、string、count

4、返回值

返回带有替换值的字符串或数组。

5、实例

创建一个PHP示例文件；然后通过“tr_replace($vowels, "","Hello World of PHP");”方法替换多个字符串即可。


echo str_replace(array("m","i"),array("n","z"),"my name is jim!")

echo str_replace(array('m','i'),'n',"my name is jim!");

$vowels = array("a", "e", "i", "o", "u", "A", "E", "I", "O", "U");

$onlyconsonants = str_replace($vowels, "","Hello World of PHP");
echo $onlyconsonants;

知识点扩展：

PHP利用str_replace防注入的方法


   <?php
    /**
    * 安全过滤函数
    *
    * @param $string
    * @return string
    */
    function safe_replace($string) {
    $string = str_replace('%20','',$string);
    $string = str_replace('%27','',$string);
    $string = str_replace('%2527','',$string);
    $string = str_replace('*','',$string);
    $string = str_replace('"','&quot;',$string);
    $string = str_replace("'",'',$string);
    $string = str_replace('"','',$string);
    $string = str_replace(';','',$string);
    $string = str_replace('<','&lt;',$string);
    $string = str_replace('>','&gt;',$string);
    $string = str_replace("{",'',$string);
    $string = str_replace('}','',$string);
    $string = str_replace('','',$string);
    return $string;
    }
    ?>

    <?php
    /**
    * 返回经addslashes处理过的字符串或数组
    * @param $string 需要处理的字符串或数组
    * @return mixed
    */
    function new_addslashes($string) {
    if(!is_array($string)) return addslashes($string);
    foreach($string as $key => $val) $string[$key] = new_addslashes($val);
    return $string;
    }
    ?>

    <?php
    //对请求的字符串进行安全处理
    /*
    $safestep
    0 为不处理，
    1 为禁止不安全HTML内容(javascript等)，
    2 完全禁止HTML内容，并替换部份不安全字符串（如：eval(、union、CONCAT(、--、等）
    */
    function StringSafe($str, $safestep=-1){
    $safestep = ($safestep > -1) ? $safestep : 1;
    if($safestep == 1){
    $str = preg_replace("#script:#i", "ｓｃｒｉｐｔ：", $str);
    $str = preg_replace("#<[/]{0,1}(link|meta|ifr|fra|scr)[^>]*>#isU", '', $str);
    $str = preg_replace("#[ ]{1,}#", ' ', $str);
    return $str;
    }else if($safestep == 2){
    $str = addslashes(htmlspecialchars(stripslashes($str)));
    $str = preg_replace("#eval#i", 'ｅｖａｌ', $str);
    $str = preg_replace("#union#i", 'ｕｎｉｏｎ', $str);
    $str = preg_replace("#concat#i", 'ｃｏｎｃａｔ', $str);
    $str = preg_replace("#--#", '－－', $str);
    $str = preg_replace("#[ ]{1,}#", ' ', $str);
    return $str;
    }else{
    return $str;
    }
    }
    ?>

    <?php
       /**
        +----------------------------------------------------------
        * 输出安全的html，用于过滤危险代码
        +----------------------------------------------------------
        * @access public
        +----------------------------------------------------------
        * @param string $text 要处理的字符串
        * @param mixed $tags 允许的标签列表，如 table|td|th|td
        +----------------------------------------------------------
        * @return string
        +----------------------------------------------------------
        */
       static public function safeHtml($text, $tags = null)
       {
           $text =  trim($text);
           //完全过滤注释
           $text = preg_replace('/<!--?.*-->/','',$text);
           //完全过滤动态代码
           $text =  preg_replace('/<?|?'.'>/','',$text);
           //完全过滤js
           $text = preg_replace('/<script?.*/script>/','',$text);
           $text =  str_replace('[','&#091;',$text);
           $text = str_replace(']','&#093;',$text);
           $text =  str_replace('|','&#124;',$text);
           //过滤换行符
           $text = preg_replace('/ ? /','',$text);
           //br
           $text =  preg_replace('/<br(s/)?'.'>/i','[br]',$text);
           $text = preg_replace('/([br]s*){10,}/i','[br]',$text);
           //过滤危险的属性，如：过滤on事件lang js
           while(preg_match('/(<[^><]+)(lang|on|action|background|codebase|dynsrc|lowsrc)[^><]+/i',$text,$mat)){
               $text=str_replace($mat[0],$mat[1],$text);
           }
           while(preg_match('/(<[^><]+)(window.|javascript:|js:|about:|file:|document.|vbs:|cookie)([^><]*)/i',$text,$mat)){
               $text=str_replace($mat[0],$mat[1].$mat[3],$text);
           }
           if( empty($allowTags) ) { $allowTags = self::$htmlTags['allow']; }
           //允许的HTML标签
           $text =  preg_replace('/<('.$allowTags.')( [^><[]]*)>/i','[12]',$text);
           //过滤多余html
           if ( empty($banTag) ) { $banTag = self::$htmlTags['ban']; }
           $text =  preg_replace('/</?('.$banTag.')[^><]*>/i','',$text);
           //过滤合法的html标签
           while(preg_match('/<([a-z]+)[^><[]]*>[^><]*</1>/i',$text,$mat)){
               $text=str_replace($mat[0],str_replace('>',']',str_replace('<','[',$mat[0])),$text);
           }
           //转换引号
           while(preg_match('/([[^[]]*=s*)("|')([^2=[]]+)2([^[]]*])/i',$text,$mat)){
               $text=str_replace($mat[0],$mat[1].'|'.$mat[3].'|'.$mat[4],$text);
           }
           //空属性转换
           $text =  str_replace('''','||',$text);
           $text = str_replace('""','||',$text);
           //过滤错误的单个引号
           while(preg_match('/[[^[]]*("|')[^[]]*]/i',$text,$mat)){
               $text=str_replace($mat[0],str_replace($mat[1],'',$mat[0]),$text);
           }
           //转换其它所有不合法的 < >
           $text =  str_replace('<','&lt;',$text);
           $text = str_replace('>','&gt;',$text);
           $text = str_replace('"','&quot;',$text);
           //反转换
           $text =  str_replace('[','<',$text);
           $text =  str_replace(']','>',$text);
           $text =  str_replace('|','"',$text);
           //过滤多余空格
           $text =  str_replace('  ',' ',$text);
           return $text;
       }
    ?>

    <?php
    function RemoveXSS($val) { 
       // remove all non-printable characters. CR(0a) and LF(0b) and TAB(9) are allowed 
       // this prevents some character re-spacing such as <javascript> 
       // note that you have to handle splits with , , and later since they *are* allowed in some          // inputs 
       $val = preg_replace('/([x00-x08,x0b-x0c,x0e-x19])/', '', $val); 
       // straight replacements, the user should never need these since they're normal characters 
       // this prevents like <IMG SRC=@avascript:alert('XSS')> 
       $search = 'abcdefghijklmnopqrstuvwxyz'; 
       $search .= 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'; 
       $search .= '1234567890!@#$%^&*()'; 
       $search .= '~`";:?+/={}[]-_|''; 
       for ($i = 0; $i < strlen($search); $i++) { 
           // ;? matches the ;, which is optional 
           // 0{0,7} matches any padded zeros, which are optional and go up to 8 chars 
           // @ @ search for the hex values 
           $val = preg_replace('/(&#[xX]0{0,8}'.dechex(ord($search[$i])).';?)/i', $search[$i], $val);//with a ; 
           // @ @ 0{0,7} matches '0' zero to seven times 
           $val = preg_replace('/(&#0{0,8}'.ord($search[$i]).';?)/', $search[$i], $val); // with a ; 
       } 
       // now the only remaining whitespace attacks are , , and  
       $ra1 = Array('javascript', 'vbscript', 'expression', 'applet', 'meta', 'xml', 'blink', 'link', 'style', 'script', 'embed', 'object', 'iframe', 'frame', 'frameset', 'ilayer', 'layer', 'bgsound', 'title', 'base'); 
       $ra2 = Array('onabort', 'onactivate', 'onafterprint', 'onafterupdate', 'onbeforeactivate', 'onbeforecopy', 'onbeforecut', 'onbeforedeactivate', 'onbeforeeditfocus', 'onbeforepaste', 'onbeforeprint', 'onbeforeunload', 'onbeforeupdate', 'onblur', 'onbounce', 'oncellchange', 'onchange', 'onclick', 'oncontextmenu', 'oncontrolselect', 'oncopy', 'oncut', 'ondataavailable', 'ondatasetchanged', 'ondatasetcomplete', 'ondblclick', 'ondeactivate', 'ondrag', 'ondragend', 'ondragenter', 'ondragleave', 'ondragover', 'ondragstart', 'ondrop', 'onerror', 'onerrorupdate', 'onfilterchange', 'onfinish', 'onfocus', 'onfocusin', 'onfocusout', 'onhelp', 'onkeydown', 'onkeypress', 'onkeyup', 'onlayoutcomplete', 'onload', 'onlosecapture', 'onmousedown', 'onmouseenter', 'onmouseleave', 'onmousemove', 'onmouseout', 'onmouseover', 'onmouseup', 'onmousewheel', 'onmove', 'onmoveend', 'onmovestart', 'onpaste', 'onpropertychange', 'onreadystatechange', 'onreset', 'onresize', 'onresizeend', 'onresizestart', 'onrowenter', 'onrowexit', 'onrowsdelete', 'onrowsinserted', 'onscroll', 'onselect', 'onselectionchange', 'onselectstart', 'onstart', 'onstop', 'onsubmit', 'onunload'); 
       $ra = array_merge($ra1, $ra2); 
       $found = true; // keep replacing as long as the previous round replaced something 
       while ($found == true) { 
           $val_before = $val; 
           for ($i = 0; $i < sizeof($ra); $i++) { 
               $pattern = '/'; 
               for ($j = 0; $j < strlen($ra[$i]); $j++) { 
                   if ($j > 0) { 
                       $pattern .= '('; 
                       $pattern .= '(&#[xX]0{0,8}([9ab]);)'; 
                       $pattern .= '|'; 
                       $pattern .= '|(&#0{0,8}([9|10|13]);)'; 
                       $pattern .= ')*'; 
                   } 
                   $pattern .= $ra[$i][$j]; 
               } 
               $pattern .= '/i'; 
               $replacement = substr($ra[$i], 0, 2).'<x>'.substr($ra[$i], 2); // add in <> to nerf the tag 
               $val = preg_replace($pattern, $replacement, $val); // filter out the hex tags 
               if ($val_before == $val) { 
                   // no replacements were made, so exit the loop 
                   $found = false; 
               } 
           } 
       } 
       return $val; 
    }
    ?>

到此这篇关于php中str_replace替换实例讲解的文章就介绍到这了,更多相关php中str_replace如何替换内容请搜索编程学习网以前的文章希望大家以后多多支持编程学习网！