使用PHP中的正則表達式選擇性地替換標記之外的單詞？

Question

我有一段文字，我想用PHP（preg_replace）替換一些單詞。 這是一段示例文本：

This lesson addresses rhyming [one]words and ways[/one] that students may learn to identify these words. Topics include learning that rhyming words sound alike and these sounds all come from the [two]ending of the words[/two]. This can be accomplished by having students repeat sets of rhyming words so that they can say them and hear them. The students will also participate in a variety of rhyming word activities. In order to demonstrate mastery the students will listen to [three]sets of words[/three] and tell the teacher if the words rhyme or not.

如果您注意到“單詞”一詞的出現次數很多。 我想用“ birds”一詞替換所有未在任何標簽內發生的事件。 所以看起來像這樣：

This lesson addresses rhyming [one]words and ways[/one] that students may learn to identify these birds. Topics include learning that rhyming birds sound alike and these sounds all come from the [two]ending of the words[/two]. This can be accomplished by having students repeat sets of rhyming birds so that they can say them and hear them. The students will also participate in a variety of rhyming word activities. In order to demonstrate mastery the students will listen to [three]sets of words[/three] and tell the teacher if the birds rhyme or not.

您會使用正則表達式來做到這一點嗎？
正則表達式可以做到這一點？

Answer 1

您使用的標簽未定義常規語言，因此常規表達式不適用於此。 我認為您可以做的最好的事情是刪除所有標簽（用其他東西替換它們），用“ birds”替換“ words”，然后再放回內容。

$str = preg_replace_callback('!\[one\].*?\[/one\]!s', 'hash_one', $input);
$str = str_replace('words', 'birds', $str);
$output = preg_replace_callback('!:=%\w+%=:!', 'replace_one', $str);

$hash = array();

function hash_one($matches) {
  global $hash;
  $key = ':=%' . md5($matches[0]) . '%=:'; // to ensure this doesn't occur naturally
  $hash[$key] = $matches[0];
  return $key;
}

function replace_one($amtches) {
  global $hash;
  $ret = $hash[$matches[0]];
  return $ret ? $ret : $matches[0];
}