這篇文章給大家分享的是PHP中str_replace() 函數(shù)用法及應用。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
??? /*
??? $safestep
??? 0 為不處理，
??? 1 為禁止不安全HTML內容(javascript等)，
??? 2 完全禁止HTML內容，并替換部份不安全字符串（如：eval(、union、CONCAT(、--、等）
??? */
??? function StringSafe($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; 
??? }
??? ?>