PHP preg_replace：区分大小写的匹配与区分大小写的替换
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PHP preg_replace: Case insensitive match with case sensitive replacement
提问by colin
I'm using preg_replace in PHP to find and replace specific words in a string, like this:
我在 PHP 中使用 preg_replace 来查找和替换字符串中的特定单词，如下所示：
$subject = "Apple apple";
print preg_replace('/\bapple\b/i', 'pear', $subject);
Which gives the result 'pear pear'.
这给出了结果“梨梨”。
What I'd like to be able to do is to match a word in a case insensitive way, but respect it's case when it is replaced - giving the result 'Pear pear'.
我希望能够做的是以不区分大小写的方式匹配一个单词，但在替换它时要尊重它的大小写 - 给出结果“梨梨”。
The following works, but seems a little long winded to me:
以下工作，但对我来说似乎有点冗长：
$pattern = array('/Apple\b/', '/apple\b/');
$replacement = array('Pear', 'pear');
$subject = "Apple apple";
print preg_replace($pattern, $replacement, $subject);
Is there a better way to do this?
有一个更好的方法吗？
Update: Further to an excellent query raised below, for the purposes of this task I only want to respect 'title case' - so whether or not the first letter of a word is a capital.
更新：除了下面提出的一个很好的查询之外，为了这个任务的目的，我只想尊重“标题案例”——所以一个词的第一个字母是否是大写的。
采纳答案by Alma Do
I have in mind this implementation for common case:
我想到了这种常见情况的实现：
$data = 'this is appLe and ApPle';
$search = 'apple';
$replace = 'pear';
$data = preg_replace_callback('/\b'.$search.'\b/i', function($matches) use ($replace)
{
$i=0;
return join('', array_map(function($char) use ($matches, &$i)
{
return ctype_lower($matches[0][$i++])?strtolower($char):strtoupper($char);
}, str_split($replace)));
}, $data);
//var_dump($data); //"this is peaR and PeAr"
-it's more complicated, of course, but fit original request for any position. If you're looking for only first letter, this could be an overkill (see @Jon's answer then)
- 当然，它更复杂，但适合任何职位的原始要求。如果您只寻找第一个字母，这可能有点矫枉过正（然后请参阅@Jon 的回答）
回答by Jon
You could do this with preg_replace_callback, but that's even more long winded:
你可以用 来做到这一点preg_replace_callback，但这更啰嗦：
$replacer = function($matches) {
return ctype_lower($matches[0][0]) ? 'pear' : 'Pear';
};
print preg_replace_callback('/\bapple\b/i', $replacer, $subject);
This code just looks at the capitalization of the first character of the match to determine what to replace with; you could adapt the code to do something more involved instead.
此代码仅查看匹配项的第一个字符的大小写，以确定要替换的内容；你可以修改代码来做一些更复杂的事情。
回答by Luke Madhanga
This is the solution that I used:
这是我使用的解决方案：
$result = preg_replace("/\b(foo)\b/i", "<strong></strong>", $original);
In the best words that I can I'll try explain why this works: Wrapping your search term with ()means I want to access this value later. As it is the first item in pars in the RegEx, it is accessible with $1, as you can see in the substitution parameter
用我能说的最好的话，我会尝试解释为什么会这样：将您的搜索词包装起来()意味着我想稍后访问这个值。由于它是 RegEx 中 pars 中的第一项，因此可以使用 访问$1，正如您在替换参数中看到的
