preg_match匹配两个字符时，应该只匹配一个 [英] preg_match is matching two characters when it should only match one

问题描述

我正在尝试从字符串中提取特殊字符（从预定义的模式中），但是当该字符串以反向问号开头时，matches将返回前两个字符，包括不是特殊字符。例如：

I'm trying to extract the special characters (out of a predefined pattern) from a string, but when that string begins with an inverted question mark, "matches" returns first two characters, including a not special one. Eg.:

$string = '¿hola?';

$string2 = mb_convert_encoding($string, 'UTF-8');
$regex =  mb_convert_encoding('/[a-zäáàëéèíìöóòúùñç]/', 'UTF-8');

if(preg_match($regex, $string2, $matches, PREG_OFFSET_CAPTURE))
{

  //--> We pick the special characters into "$resultado1":
  $resultado1 = mb_substr($string, 0, $matches[0][1],'UTF-8');

  return $resultado1;
}

在这个例子中，函数返回¿h，但¿预期...我无法弄清楚问题...

In this example, the function returns "¿h", but "¿" was expected... I can't figure out the problem...

推荐答案

尝试使用标志u（正如您所使用的正则表达式中的此页面所述）： / [a-zäáàëéèíìöóòúùñç] / u

Try to use the flag "u" (as documented on this page) in your regex: /[a-zäáàëéèíìöóòúùñç]/u

更喜欢将文件保存在UTF-8中，而不是在静态上使用mb_convert_encoding字符串。

And prefer saving your files in UTF-8 rather than using mb_convert_encoding on static strings.

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