我需要帮助编写将HTML字符串转换为有效XML标记名称的正则表达式函数。例如：它需要一个字符串并执行以下操作：
- 如果字符串中出现字母或下划线，则会保留它
- 如果出现任何其他字符，则会从输出字符串中删除该字符。
- 如果单词或字母之间出现任何其他字符，则会将其替换为下划线。
Ex: Input: Date Created Ouput: Date_Created Input: Date<br/>Created Output: Date_Created Input: Date'nCreated Output: Date_Created Input: Date 1 2 3 Created Output: Date_Created
基本上，正则表达式函数应该将 HTML 字符串转换为有效的 XML 标记。
一些正则表达式和一些标准函数：
function mystrip($s)
{
// add spaces around angle brackets to separate tag-like parts
// e.g. "<br />" becomes " <br /> "
// then let strip_tags take care of removing html tags
$s = strip_tags(str_replace(array('<', '>'), array(' <', '> '), $s));
// any sequence of characters that are not alphabet or underscore
// gets replaced by a single underscore
return preg_replace('/[^a-z_]+/i', '_', $s);
}
试试这个
$result = preg_replace('/(['d's]|<[^<>]+>)/', '_', $subject);
解释
"
( # Match the regular expression below and capture its match into backreference number 1
# Match either the regular expression below (attempting the next alternative only if this one fails)
['d's] # Match a single character present in the list below
# A single digit 0..9
# A whitespace character (spaces, tabs, and line breaks)
| # Or match regular expression number 2 below (the entire group fails if this one fails to match)
< # Match the character “<” literally
[^<>] # Match a single character NOT present in the list “<>”
+ # Between one and unlimited times, as many times as possible, giving back as needed (greedy)
> # Match the character “>” literally
)
"
应该能够使用：
$text = preg_replace( '/(?<=[a-zA-Z])[^a-zA-Z_]+(?=[a-zA-Z])/', '_', $text );
因此，可以环顾四周，以查看前后是否有字母字符，并替换其之间的任何非字母/非下划线。
我相信
以下内容应该有效。
preg_replace('/[^A-Za-z_]+(.*)?([^A-Za-z_]+)?/', '_', $string);
正则表达式[^A-Za-z_]+的第一部分匹配一个或多个不按字母顺序或下划线排列的字符。正则表达式的结束部分是相同的，只是它是可选的。这是为了允许中间部分（(.*)?也是可选的）捕获两个列入黑名单的字符之间的任何字符（甚至是字母和下划线）。