PHP中str_replace() 函数用法是什么？可以怎样用？

这篇文章给大家分享的是PHP中str_replace() 函数用法及应用。小编觉得挺实用的，因此分享给大家做个参考，下文会介绍str_replace函数的的概念、语法、参数、返回值等等，文中示例代码介绍的非常详细，感兴趣的朋友接下来一起跟随小编看看吧。

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;
 
 }
    
 ?>
    

以上就是关于PHP中str_replace() 函数用法及应用的介绍，上述示例具有一定的借鉴价值，有需要的朋友可以参考学习，希望对大家学习PHP函数有帮助，想要了解更多可以继续浏览网络其他相关的文章。

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