PHP preg_split同时在数组元素的开头保持分隔符

Question

我是regex的新手，我想在分隔符上分割一个字符串，同时在每个数组元素的开头保留该分隔符。我没试成功，但提出了：

    $str = 'LOTS OF STUFF AND SOME MORE STUFF AND SOME OTHER STUFF';
    $matches = preg_split('/(\ AND)/', $str, null, PREG_SPLIT_DELIM_CAPTURE);  

这会将分隔符作为自己的元素：

[0]=>"LOTS OF STUFF"
[1]=>" AND"
[2]=>" SOME MORE STUFF"
[3]=>" AND"
[4]=>" SOME OTHER STUFF"

但我想将分隔符保留在元素的开头：

[0]=>"LOTS OF STUFF"
[1]=>" AND SOME MORE STUFF"
[2]=>" AND SOME OTHER STUFF"

我想也许我可以尝试使用后视镜，但后来我再次失去了分隔符：

    $matches = preg_split('/(?<=\s)AND/', $str, null, PREG_SPLIT_DELIM_CAPTURE);

[0]=>"LOTS OF STUFF"
[1]=>" SOME MORE STUFF"
[2]=>" SOME OTHER STUFF"

非常乐意帮助，谢谢!!

Answer 1

使用lookahead assertion（(?=)）分隔跟随的字符串位置AND：

$str = 'LOTS OF STUFF AND SOME MORE STUFF AND SOME OTHER STUFF';
$matches = preg_split('/ (?=AND)/', $str); 
var_dump($matches);
/*
array(3) {
  [0]=>
  string(13) "LOTS OF STUFF"
  [1]=>
  string(19) "AND SOME MORE STUFF"
  [2]=>
  string(20) "AND SOME OTHER STUFF"
}
*/  

Demo。此代码删除AND之前的空格;如果它不是你想要的，只要摆脱正则表达式中的空白。