PHP preg_replace oddity with £ pound sign and ã

Question

我正在应用以下功能

<?php

function replaceChar($string){
    $new_string = preg_replace("/[^a-zA-Z0-9\sçéèêëñòóôõöàáâäåìíîïùúûüýÿ]/", "", $string);
    return $new_string;
}

$string = "This is some text and numbers 12345 and symbols !£%^#&$ and foreign letters éèêëñòóôõöàáâäåìíîïùúûüýÿ";

echo replaceChar($string);
?>

效果很好，但如果我将 ã 添加到 preg_replace 中，比如

$new_string = preg_replace("/[^a-zA-Z0-9\sçéèêëñòóôõöàáâãäåìíîïùúûüýÿ]/", "", $string);

$string = "This is some text and numbers 12345 and symbols !£%^#&$ and foreign letters éèêëñòóôõöàáâäåìíîïùúûüýÿã";

它与英镑符号 £ 冲突，将英镑符号替换为黑色方 block 中未识别的问号。

这并不重要，但有人知道这是为什么吗？

谢谢，

巴里

更新:谢谢大家。更改函数添加 u 修饰符:pt2.php.net/manual/en/… – 正如 Artefacto 所建议的那样，这是一种享受

function replaceChar($string){
$new_string = preg_replace("/[^a-zA-Z0-9\sçéèêëñòóôõøöàáâãäåìíîïùúûüýÿ]/u", "", $string);
return $new_string;
}

Answer 1

如果您的字符串是 UTF-8 格式，则必须将 u 修饰符添加到正则表达式中。像这样:

function replaceChar($string){
    $new_string = preg_replace("/[^a-zA-Z0-9\sçéèêëñòóôõöàáâäåìíîïùúûüýÿ]/u", "", $string);
    return $new_string;
}

$string = "This is some text and numbers 12345 and symbols !£%^#&$ and foreign letters éèêëñòóôõöàáâäåìíîïùúûüýÿ";

echo replaceChar($string);