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How to convert full-width characters to half-width characters in PHP

墨辰丷

Jun 08, 2018 pm 05:54 PM

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本篇文章主要介绍PHP实现全角字符转为半角的方法，感兴趣的朋友参考下，希望对大家有所帮助。

最简单的方法

<?php  
$str = "０１２３ＡＢＣＤＦＷＳ＼＂，．？＜＞｛｝［］＊＆＾％＃＠！～（）＋－｜：；";  
echo "$str";  
echo "<br />";  
$str = preg_replace(&#39;/\xa3([\xa1-\xfe])/e&#39;, &#39;chr(ord(\1)-0x80)&#39;, $str);  
echo $str;

这是网上看来的代码，所有的中文标点的第二个字节减去0X80（即128）所得的数字就是半角所得的数字了。而/e模式表达的是：如果设定了此修正符，preg_replace() 在替换字符串中对逆向引用作正常的替换，将其作为 PHP 代码求值，并用其结果来替换所搜索的字符串。

在非UTF-8模式下这个函数是可行的,但是UTF-8下这个方法就似乎无效,

方法二：

$queue = Array(&#39;０&#39; => &#39;0&#39;, &#39;１&#39; => &#39;1&#39;, &#39;２&#39; => &#39;2&#39;, &#39;３&#39; => &#39;3&#39;, &#39;４&#39; => &#39;4&#39;, &#39;５&#39; => &#39;5&#39;, &#39;６&#39; => &#39;6&#39;, &#39;７&#39; => &#39;7&#39;, &#39;８&#39; => &#39;8&#39;, &#39;９&#39; => &#39;9&#39;, 
&#39;Ａ&#39; => &#39;A&#39;, &#39;Ｂ&#39; => &#39;B&#39;, &#39;Ｃ&#39; => &#39;C&#39;, &#39;Ｄ&#39; => &#39;D&#39;, &#39;Ｅ&#39; => &#39;E&#39;, &#39;Ｆ&#39; => &#39;F&#39;, &#39;Ｇ&#39; => &#39;G&#39;, &#39;Ｈ&#39; => &#39;H&#39;, &#39;Ｉ&#39; => &#39;I&#39;, &#39;Ｊ&#39; => &#39;J&#39;, 
&#39;Ｋ&#39; => &#39;K&#39;, &#39;Ｌ&#39; => &#39;L&#39;, &#39;Ｍ&#39; => &#39;M&#39;, &#39;Ｎ&#39; => &#39;N&#39;, &#39;Ｏ&#39; => &#39;O&#39;, &#39;Ｐ&#39; => &#39;P&#39;, &#39;Ｑ&#39; => &#39;Q&#39;, &#39;Ｒ&#39; => &#39;R&#39;, &#39;Ｓ&#39; => &#39;S&#39;, &#39;Ｔ&#39; => &#39;T&#39;, 
&#39;Ｕ&#39; => &#39;U&#39;, &#39;Ｖ&#39; => &#39;V&#39;, &#39;Ｗ&#39; => &#39;W&#39;, &#39;Ｘ&#39; => &#39;X&#39;, &#39;Ｙ&#39; => &#39;Y&#39;, &#39;Ｚ&#39; => &#39;Z&#39;, &#39;ａ&#39; => &#39;a&#39;, &#39;ｂ&#39; => &#39;b&#39;, &#39;ｃ&#39; => &#39;c&#39;, &#39;ｄ&#39; => &#39;d&#39;, 
&#39;ｅ&#39; => &#39;e&#39;, &#39;ｆ&#39; => &#39;f&#39;, &#39;ｇ&#39; => &#39;g&#39;, &#39;ｈ&#39; => &#39;h&#39;, &#39;ｉ&#39; => &#39;i&#39;, &#39;ｊ&#39; => &#39;j&#39;, &#39;ｋ&#39; => &#39;k&#39;, &#39;ｌ&#39; => &#39;l&#39;, &#39;ｍ&#39; => &#39;m&#39;, &#39;ｎ&#39; => &#39;n&#39;, 
&#39;ｏ&#39; => &#39;o&#39;, &#39;ｐ&#39; => &#39;p&#39;, &#39;ｑ&#39; => &#39;q&#39;, &#39;ｒ&#39; => &#39;r&#39;, &#39;ｓ&#39; => &#39;s&#39;, &#39;ｔ&#39; => &#39;t&#39;, &#39;ｕ&#39; => &#39;u&#39;, &#39;ｖ&#39; => &#39;v&#39;, &#39;ｗ&#39; => &#39;w&#39;, &#39;ｘ&#39; => &#39;x&#39;, 
&#39;ｙ&#39; => &#39;y&#39;, &#39;ｚ&#39; => &#39;z&#39;);
echo preg_replace_callback("/([\xEF][\xBC][\x90-\x99]|[\xEF][\xBD][\x81-\x9A\xA1-\xBA])/", &#39;next_fchar&#39;, &#39;０&#39;);
function next_fchar($matches){
 global $queue;
 return $queue[$matches[1]];
}

方法三：

/**
* 字符串半角和全角间相互转换
* @param string $str 待转换的字符串
* @param int  $type TODBC:转换为半角；TOSBC，转换为全角
* @return string 返回转换后的字符串
*/
function convertStrType($str, $type) {
    $dbc = array( 
      &#39;０&#39; , &#39;１&#39; , &#39;２&#39; , &#39;３&#39; , &#39;４&#39; , 
      &#39;５&#39; , &#39;６&#39; , &#39;７&#39; , &#39;８&#39; , &#39;９&#39; , 
      &#39;Ａ&#39; , &#39;Ｂ&#39; , &#39;Ｃ&#39; , &#39;Ｄ&#39; , &#39;Ｅ&#39; , 
      &#39;Ｆ&#39; , &#39;Ｇ&#39; , &#39;Ｈ&#39; , &#39;Ｉ&#39; , &#39;Ｊ&#39; , 
      &#39;Ｋ&#39; , &#39;Ｌ&#39; , &#39;Ｍ&#39; , &#39;Ｎ&#39; , &#39;Ｏ&#39; , 
      &#39;Ｐ&#39; , &#39;Ｑ&#39; , &#39;Ｒ&#39; , &#39;Ｓ&#39; , &#39;Ｔ&#39; , 
      &#39;Ｕ&#39; , &#39;Ｖ&#39; , &#39;Ｗ&#39; , &#39;Ｘ&#39; , &#39;Ｙ&#39; , 
      &#39;Ｚ&#39; , &#39;ａ&#39; , &#39;ｂ&#39; , &#39;ｃ&#39; , &#39;ｄ&#39; , 
      &#39;ｅ&#39; , &#39;ｆ&#39; , &#39;ｇ&#39; , &#39;ｈ&#39; , &#39;ｉ&#39; , 
      &#39;ｊ&#39; , &#39;ｋ&#39; , &#39;ｌ&#39; , &#39;ｍ&#39; , &#39;ｎ&#39; , 
      &#39;ｏ&#39; , &#39;ｐ&#39; , &#39;ｑ&#39; , &#39;ｒ&#39; , &#39;ｓ&#39; , 
      &#39;ｔ&#39; , &#39;ｕ&#39; , &#39;ｖ&#39; , &#39;ｗ&#39; , &#39;ｘ&#39; , 
      &#39;ｙ&#39; , &#39;ｚ&#39; , &#39;－&#39; , &#39;　&#39; , &#39;：&#39; ,
      &#39;．&#39; , &#39;，&#39; , &#39;／&#39; , &#39;％&#39; , &#39;＃&#39; ,
      &#39;！&#39; , &#39;＠&#39; , &#39;＆&#39; , &#39;（&#39; , &#39;）&#39; ,
      &#39;＜&#39; , &#39;＞&#39; , &#39;＂&#39; , &#39;＇&#39; , &#39;？&#39; ,
      &#39;［&#39; , &#39;］&#39; , &#39;｛&#39; , &#39;｝&#39; , &#39;＼&#39; ,
      &#39;｜&#39; , &#39;＋&#39; , &#39;＝&#39; , &#39;＿&#39; , &#39;＾&#39; ,
      &#39;￥&#39; , &#39;￣&#39; , &#39;｀&#39;
);
    $sbc = array( //半角
      &#39;0&#39;, &#39;1&#39;, &#39;2&#39;, &#39;3&#39;, &#39;4&#39;, 
      &#39;5&#39;, &#39;6&#39;, &#39;7&#39;, &#39;8&#39;, &#39;9&#39;, 
      &#39;A&#39;, &#39;B&#39;, &#39;C&#39;, &#39;D&#39;, &#39;E&#39;, 
      &#39;F&#39;, &#39;G&#39;, &#39;H&#39;, &#39;I&#39;, &#39;J&#39;, 
      &#39;K&#39;, &#39;L&#39;, &#39;M&#39;, &#39;N&#39;, &#39;O&#39;, 
      &#39;P&#39;, &#39;Q&#39;, &#39;R&#39;, &#39;S&#39;, &#39;T&#39;, 
      &#39;U&#39;, &#39;V&#39;, &#39;W&#39;, &#39;X&#39;, &#39;Y&#39;, 
      &#39;Z&#39;, &#39;a&#39;, &#39;b&#39;, &#39;c&#39;, &#39;d&#39;, 
      &#39;e&#39;, &#39;f&#39;, &#39;g&#39;, &#39;h&#39;, &#39;i&#39;, 
      &#39;j&#39;, &#39;k&#39;, &#39;l&#39;, &#39;m&#39;, &#39;n&#39;, 
      &#39;o&#39;, &#39;p&#39;, &#39;q&#39;, &#39;r&#39;, &#39;s&#39;, 
      &#39;t&#39;, &#39;u&#39;, &#39;v&#39;, &#39;w&#39;, &#39;x&#39;, 
      &#39;y&#39;, &#39;z&#39;, &#39;-&#39;, &#39; &#39;, &#39;:&#39;,
      &#39;.&#39;, &#39;,&#39;, &#39;/&#39;, &#39;%&#39;, &#39; #&#39;,
      &#39;!&#39;, &#39;@&#39;, &#39;&&#39;, &#39;(&#39;, &#39;)&#39;,
      &#39;<&#39;, &#39;>&#39;, &#39;"&#39;, &#39;\&#39;&#39;,&#39;?&#39;,
      &#39;[&#39;, &#39;]&#39;, &#39;{&#39;, &#39;}&#39;, &#39;\\&#39;,
      &#39;|&#39;, &#39;+&#39;, &#39;=&#39;, &#39;_&#39;, &#39;^&#39;,
      &#39;￥&#39;,&#39;~&#39;, &#39;`&#39;
);
if($type == &#39;TODBC&#39;){
return str_replace( $sbc, $dbc, $str ); //半角到全角
}elseif($type == &#39;TOSBC&#39;){
return str_replace( $dbc, $sbc, $str ); //全角到半角
}else{
return $str;
}
}

方法四：

/**
* 将一个字串中含有全角的数字字符、字母、空格或&#39;%+-()&#39;字符转换为相应半角字符
*
* @access public
* @param string $str 待转换字串
*
* @return string $str 处理后字串
*/
function make_semiangle($str)
{
$arr = array(&#39;０&#39; => &#39;0&#39;, &#39;１&#39; => &#39;1&#39;, &#39;２&#39; => &#39;2&#39;, &#39;３&#39; => &#39;3&#39;, &#39;４&#39; => &#39;4&#39;,
&#39;５&#39; => &#39;5&#39;, &#39;６&#39; => &#39;6&#39;, &#39;７&#39; => &#39;7&#39;, &#39;８&#39; => &#39;8&#39;, &#39;９&#39; => &#39;9&#39;,
&#39;Ａ&#39; => &#39;A&#39;, &#39;Ｂ&#39; => &#39;B&#39;, &#39;Ｃ&#39; => &#39;C&#39;, &#39;Ｄ&#39; => &#39;D&#39;, &#39;Ｅ&#39; => &#39;E&#39;,
&#39;Ｆ&#39; => &#39;F&#39;, &#39;Ｇ&#39; => &#39;G&#39;, &#39;Ｈ&#39; => &#39;H&#39;, &#39;Ｉ&#39; => &#39;I&#39;, &#39;Ｊ&#39; => &#39;J&#39;,
&#39;Ｋ&#39; => &#39;K&#39;, &#39;Ｌ&#39; => &#39;L&#39;, &#39;Ｍ&#39; => &#39;M&#39;, &#39;Ｎ&#39; => &#39;N&#39;, &#39;Ｏ&#39; => &#39;O&#39;,
&#39;Ｐ&#39; => &#39;P&#39;, &#39;Ｑ&#39; => &#39;Q&#39;, &#39;Ｒ&#39; => &#39;R&#39;, &#39;Ｓ&#39; => &#39;S&#39;, &#39;Ｔ&#39; => &#39;T&#39;,
&#39;Ｕ&#39; => &#39;U&#39;, &#39;Ｖ&#39; => &#39;V&#39;, &#39;Ｗ&#39; => &#39;W&#39;, &#39;Ｘ&#39; => &#39;X&#39;, &#39;Ｙ&#39; => &#39;Y&#39;,
&#39;Ｚ&#39; => &#39;Z&#39;, &#39;ａ&#39; => &#39;a&#39;, &#39;ｂ&#39; => &#39;b&#39;, &#39;ｃ&#39; => &#39;c&#39;, &#39;ｄ&#39; => &#39;d&#39;,
&#39;ｅ&#39; => &#39;e&#39;, &#39;ｆ&#39; => &#39;f&#39;, &#39;ｇ&#39; => &#39;g&#39;, &#39;ｈ&#39; => &#39;h&#39;, &#39;ｉ&#39; => &#39;i&#39;,
&#39;ｊ&#39; => &#39;j&#39;, &#39;ｋ&#39; => &#39;k&#39;, &#39;ｌ&#39; => &#39;l&#39;, &#39;ｍ&#39; => &#39;m&#39;, &#39;ｎ&#39; => &#39;n&#39;,
&#39;ｏ&#39; => &#39;o&#39;, &#39;ｐ&#39; => &#39;p&#39;, &#39;ｑ&#39; => &#39;q&#39;, &#39;ｒ&#39; => &#39;r&#39;, &#39;ｓ&#39; => &#39;s&#39;,
&#39;ｔ&#39; => &#39;t&#39;, &#39;ｕ&#39; => &#39;u&#39;, &#39;ｖ&#39; => &#39;v&#39;, &#39;ｗ&#39; => &#39;w&#39;, &#39;ｘ&#39; => &#39;x&#39;,
&#39;ｙ&#39; => &#39;y&#39;, &#39;ｚ&#39; => &#39;z&#39;,
&#39;（&#39; => &#39;(&#39;, &#39;）&#39; => &#39;)&#39;, &#39;〔&#39; => &#39;[&#39;, &#39;〕&#39; => &#39;]&#39;, &#39;【&#39; => &#39;[&#39;,
&#39;】&#39; => &#39;]&#39;, &#39;〖&#39; => &#39;[&#39;, &#39;〗&#39; => &#39;]&#39;, &#39;“&#39; => &#39;[&#39;, &#39;”&#39; => &#39;]&#39;,
&#39;‘&#39; => &#39;[&#39;, &#39;&#39;&#39; => &#39;]&#39;, &#39;｛&#39; => &#39;{&#39;, &#39;｝&#39; => &#39;}&#39;, &#39;《&#39; => &#39;<&#39;,
&#39;》&#39; => &#39;>&#39;,
&#39;％&#39; => &#39;%&#39;, &#39;＋&#39; => &#39;+&#39;, &#39;—&#39; => &#39;-&#39;, &#39;－&#39; => &#39;-&#39;, &#39;～&#39; => &#39;-&#39;,
&#39;：&#39; => &#39;:&#39;, &#39;。&#39; => &#39;.&#39;, &#39;、&#39; => &#39;,&#39;, &#39;，&#39; => &#39;.&#39;, &#39;、&#39; => &#39;.&#39;,
&#39;；&#39; => &#39;,&#39;, &#39;？&#39; => &#39;?&#39;, &#39;！&#39; => &#39;!&#39;, &#39;…&#39; => &#39;-&#39;, &#39;‖&#39; => &#39;|&#39;,
&#39;”&#39; => &#39;"&#39;, &#39;&#39;&#39; => &#39;`&#39;, &#39;‘&#39; => &#39;`&#39;, &#39;｜&#39; => &#39;|&#39;, &#39;〃&#39; => &#39;"&#39;,
&#39;　&#39; => &#39; &#39;);
return strtr($str, $arr);
}

全角与半角之区别（来自中文维基百科）

全角，又称全形、全宽，是电脑字符的一种格式，字面意思是比普通字符（或半角字符）宽的字符。

传统上，英语或拉丁字母语言使用一字节的空间来存储，而汉字、日语等常使用两字节存储，在使用固定宽度文字的地方，为了使字体看起来整齐，英文字母、数字及其他符号，也由原来只占用一个字空间，改为一概占用两个字的空间来显示，并且使用两个字节来存储。

总结：以上就是本篇文的全部内容，希望能对大家的学习有所帮助。

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