将HTML格式的字符串插入另一个字符串 - Insert HTML formatted string into another string

我有两个字符串。其中一个包含标记，完全小写，不包含分隔符或常用词，如"the"、"in"等，而另一个则不包含。一个例子：

$str1 = 'world <em>round</em>';
$str2 = 'World - is Round';

我想通过比较$str1中的哪个小写单词包含标签，将$str2设为'World - is Round'。到目前为止，我已经完成了以下操作，但如果两个字符串中的单词数量不相等，则失败。

public static function applyHighlighingOnDisplayName($str1, $str2) {
    $str1_w = explode(' ', $str1);
    $str2_w = explode(' ', $str2);
    for ($i=0; $i<count($str1_w); $i++) {
       if (strpos($str1_w[$i], '<em>') !== false) {
            $str2_w[$i] = '<em>' . $str2_w[$i] . '</em>';
       }
    }
    return implode(' ', $str2_w);
}
$str1 = '<em>cup</em> <em>cakes</em>' & $str2 = 'Cup Cakes':
applyHighlighingOnDisplayName($str1, $str2) : '<em>Cup</em> <em>Cakes</em>': Correct
$str1 = 'cup <em>cakes</em>' & $str2 = 'The Cup Cakes':
applyHighlighingOnDisplayName($str1, $str2) : 'The <em>Cup</em> Cakes: Incorrect

我应该如何改变我的方法？

正如其他人所说，regex就是解决方案。以下是一个带有详细注释的工作示例：

$string1 = 'world <em>round</em>';
$string2 = 'World is - Round';
// extract what's in between <em> and </em> - it will be stored in $matches[1]
preg_match('/<em>(.+)<'/em>/i', $string1, $matches);
if (!$matches) {
    echo 'The first string does not contain <em>';
    exit();
}
// replace what we found in the previous operation
$newString = preg_replace('/'b' . preg_quote($matches[1], ''b/') . '/i', '<em>$0</em>', $string2);
echo $newString;

详细信息：

http://php.net/manual/en/function.preg-replace.php
http://php.net/manual/en/function.preg-match.php

后期编辑-涵盖多个案例：

$string1 = 'world <em>round</em> not <em>flat</em>';
$string2 = 'World is - Round not Flat! Round, ok?';
// extract what's in between <em> and </em> - it will be stored in $matches[1]
preg_match_all('/<em>(.+?)<'/em>/i', $string1, $matches);
if (!$matches) {
    echo 'The first string does not contain <em>';
    exit();
}
foreach ($matches[1] as $match) {
    // replace what we found in the previous operation
    $string2 = preg_replace('/'b' . preg_quote($match) . ''b/i', '<em>$0</em>', $string2);
}
echo $string2;

您当前的方法取决于字符串中的字数；更好的解决方案是使用正则表达式为您进行匹配。即使你强调了其他强调词的子串，下面的版本也会安全地工作（例如"猫"answers"猫的摇篮"或"猫砂"）。

function applyHighlighingOnDisplayName($str1, $str2) {
    # if we have strings surrounded by <em> tags...
    if (preg_match_all("#<em>(.+?)</em>#", $str1, $match)) {
        ## sort the match strings by length, descending
        usort($match[1], function($a,$b){ return strlen($b) - strlen($a); } );
        # all the match words are in $match[1]
        foreach ($match[1] as $m) {
            # replace every match with a string that is very unlikely to occur
            # this prevents 'b matching the start or end of <em> and </em>
            $str2 = preg_replace("#'b($m)'b#i",
                "ZZZZ$1ZZZZ",
                $str2);
        }
        # replace ZZZZ with the <em> tags
        return preg_replace("#ZZZZ(.*?)ZZZZ#", "<em>$1</em>", $str2);
    }
    return $str2;
}
$str1 = 'cup <em>cakes</em>';
$str2 = 'Cup Cakes';
print applyHighlighingOnDisplayName($str1, $str2) . PHP_EOL;

输出：

Cup <em>Cakes</em>
The Cup <em>Cakes</em>

两个没有'd字的字符串：

$str1 = 'cup cakes';
$str2 = 'Cup Cakes';
print applyHighlighingOnDisplayName($str1, $str2) . PHP_EOL;

输出：

Cup Cakes

现在有一些更棘手的事情：很多短单词，其中一个单词是所有其他单词的子字符串：

$str1 = 'i if in i''ve is it';
$str2 = 'I want to make the str2 as "World - is Round", by comparing which lowercase word in the str1 contains the em tag. So far, I''ve done the following, but it fails if number of words aren''t equal in both strings.';

输出：

I want to make the str2 as "World - is Round", by comparing which lowercase word in the str1 contains the em tag. So far, I've done the following, but it fails if number of words aren't equal in both strings.

这是因为高亮显示代码期望两个字符串中的单词位置之间1:1对应：

cup <em>cakes</em>
 1        2
Cup     Cakes

但在你不正确的样品上：

cup <em>cakes</em>
 1        2            3
The      Cup         Cakes

例如，你在单词#2找到，所以你在另一个字符串中突出显示单词#2，但在那个字符串中，单词#2是Cup。

一个更好的算法是从原始字符串中剥离html，这样您最终只得到cup cakes。然后在另一个字符串中查找cup cakes，并突出显示该位置的第二个单词。这将补偿字符串中由额外（或更少）单词引起的任何"运动"。