這篇文章給大家分享的是PHP中str_replace() 函數(shù)用法及應(yīng)用。小編覺得挺實用的，因此分享給大家做個參考，下文會介紹str_replace函數(shù)的的概念、語法、參數(shù)、返回值等等，文中示例代碼介紹的非常詳細，感興趣的朋友接下來一起跟隨小編看看吧。

    1、概念

    str_replace() 函數(shù)以其他字符替換字符串中的一些字符（區(qū)分大小寫）。

    該函數(shù)區(qū)分大小寫。請使用 str_ireplace() 函數(shù)執(zhí)行不區(qū)分大小寫的搜索。

    2、語法

str_replace(find,replace,string,count)

    3、參數(shù)

    Find、replace、string、count

    4、返回值

    返回帶有替換值的字符串或數(shù)組。

    5、實例

    創(chuàng)建一個PHP示例文件；然后通過“tr_replace($vowels, “”,”Hello World of PHP”);”方法替換多個字符串即可。

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;

    知識點擴展：

    PHP利用str_replace防注入的方法

   <?php
    /**
    * 安全過濾函數(shù)
    *
    * @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
    /**
    * 返回經(jīng)addslashes處理過的字符串或數(shù)組
    * @param $string 需要處理的字符串或數(shù)組
    * @return mixed
    */
    function new_addslashes($string) {
    if(!is_array($string)) return addslashes($string);
    foreach($string as $key => $val) $string[$key] = new_addslashes($val);
    return $string;
    }
    ?>

    <?php
    //對請求的字符串進行安全處理
    /*
    $safestep
    0 為不處理，
    1 為禁止不安全HTML內(nèi)容(javascript等)，
    2 完全禁止HTML內(nèi)容，并替換部份不安全字符串（如：eval(、union、CONCAT(、--、等）
    */
    function StringSafe($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
       /**
        +----------------------------------------------------------
        * 輸出安全的html，用于過濾危險代碼
        +----------------------------------------------------------
        * @access public
        +----------------------------------------------------------
        * @param string $text 要處理的字符串
        * @param mixed $tags 允許的標簽列表，如 table|td|th|td
        +----------------------------------------------------------
        * @return string
        +----------------------------------------------------------
        */
       static public function safeHtml($text, $tags = null)
       {
           $text =  trim($text);
           //完全過濾注釋
           $text = preg_replace('/<!--?.*-->/','',$text);
           //完全過濾動態(tài)代碼
           $text =  preg_replace('/<?|?'.'>/','',$text);
           //完全過濾js
           $text = preg_replace('/<script?.*/script>/','',$text);
           $text =  str_replace('[','&#091;',$text);
           $text = str_replace(']','&#093;',$text);
           $text =  str_replace('|','&#124;',$text);
           //過濾換行符
           $text = preg_replace('/ ? /','',$text);
           //br
           $text =  preg_replace('/<br(s/)?'.'>/i','[br]',$text);
           $text = preg_replace('/([br]s*){10,}/i','[br]',$text);
           //過濾危險的屬性，如：過濾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']; }
           //允許的HTML標簽
           $text =  preg_replace('/<('.$allowTags.')( [^><[]]*)>/i','[12]',$text);
           //過濾多余html
           if ( empty($banTag) ) { $banTag = self::$htmlTags['ban']; }
           $text =  preg_replace('/</?('.$banTag.')[^><]*>/i','',$text);
           //過濾合法的html標簽
           while(preg_match('/<([a-z]+)[^><[]]*>[^><]*</1>/i',$text,$mat)){
               $text=str_replace($mat[0],str_replace('>',']',str_replace('<','[',$mat[0])),$text);
           }
           //轉(zhuǎn)換引號
           while(preg_match('/([[^[]]*=s*)("|')([^2=[]]+)2([^[]]*])/i',$text,$mat)){
               $text=str_replace($mat[0],$mat[1].'|'.$mat[3].'|'.$mat[4],$text);
           }
           //空屬性轉(zhuǎn)換
           $text =  str_replace('''','||',$text);
           $text = str_replace('""','||',$text);
           //過濾錯誤的單個引號
           while(preg_match('/[[^[]]*("|')[^[]]*]/i',$text,$mat)){
               $text=str_replace($mat[0],str_replace($mat[1],'',$mat[0]),$text);
           }
           //轉(zhuǎn)換其它所有不合法的 < >
           $text =  str_replace('<','&lt;',$text);
           $text = str_replace('>','&gt;',$text);
           $text = str_replace('"','&quot;',$text);
           //反轉(zhuǎn)換
           $text =  str_replace('[','<',$text);
           $text =  str_replace(']','>',$text);
           $text =  str_replace('|','"',$text);
           //過濾多余空格
           $text =  str_replace('  ',' ',$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; 
    }
    ?>