替换 PHP 字符串中选定的字符
我知道这个问题肯定已经被问过好几次了，但是我在正则表达式方面遇到了问题...所以这是我想在 PHP 中做的（简单）事情：
我想创建一个函数来替换字符串中不需要的字符。接受的字符应该是： az AZ 0-9 _ - + ( ) { } # äöü äÖÜ 空格
我希望所有其他字符都更改为“_”。这是一些示例代码，但我不知道要填写什么 ??????:
<?php
// sample strings
$string1 = 'abd92 s_öse';
$string2 = 'ab! sd$ls_o';
// Replace unwanted chars in string by _
$string1 = preg_replace(?????, '_', $string1);
$string2 = preg_replace(?????, '_', $string2);
?>
输出应该是： $string1: abd92 s_öse (相同) $string2: ab_ sd_ls_o
我能够使其适用于 az, 0-9，但最好允许这些附加字符，尤其是 äöü。感谢您的投入！
I know this question has been asked several times for sure, but I have my problems with regular expressions... So here is the (simple) thing I want to do in PHP:
I want to make a function which replaces unwanted characters of strings. Accepted characters should be:
a-z A-Z 0-9 _ - + ( ) { } # äöü ÄÖÜ space
I want all other characters to change to a "_". Here is some sample code, but I don't know what to fill in for the ?????:
<?php
// sample strings
$string1 = 'abd92 s_öse';
$string2 = 'ab! sd$ls_o';
// Replace unwanted chars in string by _
$string1 = preg_replace(?????, '_', $string1);
$string2 = preg_replace(?????, '_', $string2);
?>
Output should be:
$string1: abd92 s_öse (the same)
$string2: ab_ sd_ls_o
I was able to make it work for a-z, 0-9 but it would be nice to allow those additional characters, especially äöü. Thanks for your input!
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仅允许您描述的确切字符：
允许所有空白，而不仅仅是（空格）字符：
允许来自不同字母表的字母 - 不仅是您提到的特定字符，还包括俄语和希腊语或其他类型的字母重音符号：
如果我是你，我会选择最后一个。它不仅更短、更容易阅读，而且限制更少，而且如果
äöüäÖÜ都很好的话，阻止像и这样的东西并没有什么特别的优势。To allow only the exact characters you described:
To allow all whitespace, not just the (space) character:
To allow letters from different alphabets -- not just the specific ones you mentioned, but also things like Russian and Greek, or other types of accent marks:
If I were you, I'd go with the last one. Not only is it shorter and easier to read, but it's less restrictive, and there's no particular advantage to blocking stuff like
иifäöüÄÖÜare all fine.将
[^a-zA-Z0-9_\-+(){}#äöüäÖÜ ]替换为_。^之后的所有字符。这将替换除 [字符集] 编辑： 中转义
-破折号的Replace
[^a-zA-Z0-9_\-+(){}#äöüÄÖÜ ]with_.This replaces any characters except the ones after
^in the [character set]Edit: escaped the
-dash.