正則表達式匹配相同的單詞

Question

假設YES 、 OR和YES是隨機詞（前提是 2 個YES是相同的）並且僅用於表示：

我正在嘗試使用正則表達式在任何地方匹配YES 、 OR和YES ，條件是字符串必須僅匹配 2 YES 。

因此，如果我嘗試使用以下測試字符串：

yes or yes
no or yes
yes or no
maybe yes or yes
maybe yes or no
yes maybe or yes
maybe yes maybe yes maybe or

它應該只匹配以下內容：

yes or yes
maybe yes or yes
yes maybe or yes
maybe yes maybe yes maybe or

這是我正在處理的正則表達式查詢：

^(?=.*(?=\w.*yes)(?=\w.*or)(?=\w.*yes)).*

不幸的是，我的查詢仍然匹配no or yes 。 這是我的正則表達式鏈接：單擊此處

Answer 1

為什么不這樣？

^(?=.*\byes\b.+\byes\b)(?=.*\bor\b).+

第一個 Positive Lookahead 找到兩個yes ，第二個匹配or

regex101 上的演示

Answer 2

使用substr_count()非正則表達式方式

<?php
$string = 'yes or yes
no or yes
yes or no
maybe yes or yes
maybe yes or no
yes maybe or yes
maybe yes maybe yes maybe or';
$array =   explode("\n", $string);
$expected = [];
//print_r($array);
foreach($array as $line){
    $words = substr_count($line,'yes');
    if($words==2 && strpos($line, 'or') !== false ){
     $expected[]= $line;   
    }
}

echo implode("\n",$expected);

輸出：

yes or yes
maybe yes or yes
yes maybe or yes
maybe yes maybe yes maybe or

演示： https : //3v4l.org/uL7fJ