PHP正则表达式意外的比赛

Question

我在我的PHP代码中的正则表达式应该每个数字和所有的“运营商” +匹配 - */^ R（）我的正则表达式看起来像这样

/(?:(\d+(?:\.\d+)|(\+)|(-)|(\*)|(\/)|(\^)|(r)|(\()|(\))))/

和测试时以字符串preg_match_all($expression,"2+2",$results)它给我回

Array 
(
    [0] => Array 
     (
      [0] => '+' 
     ) 

    [1] => Array 
     (
      [0] => '' 
     ) 

    [2] => Array 
     (
      [0] => '+' 
     ) 

    [3] => Array 
     (
      [0] => '' 
     ) 

    [4] => Array 
     (
      [0] => '' 
    ) 

    [5] => Array 
     (
      [0] => '' 
     ) 

    [6] => Array 
     (
      [0] => '' 
     ) 

    [7] => Array 
     (
      [0] => '' 
     ) 

    [8] => Array 
     ( 
      [0] => '' 
     ) 

    [9] => Array 
     (
      [0] => '' 
     ) 

) 

当（如果它的工作原理右）我应该得到这个

Array 
(
    [0] => Array 
     (
      [0] => '2' 
      [1] => '+' 
      [2] => '2' 
     ) 

    [1] => Array 
     (
      [0] => '2' 
      [1] => '' 
      [2] => '2' 
     ) 

    [2] => Array 
     (
      [0] => '' 
      [1] => '+' 
      [2] = > '' 
     ) 

    [3] => Array 
     (
      [0] => '' 
      [1] => '' 
      [2] => '' 
     ) 

    [4] => Array 
     (
      [0] => '' 
      [1] => '' 
      [2] => '' 
     ) 
    ... 

) 

注意，它返回类似行为对于所有的运营商，它似乎忽略的数字完全

注意，我确实需要单独的捕捉组，所以我有不同的匹配指标。对于每个结果

Answer 1

你可以简单地做到这一点：

$pattern = '~\d+(?:\.\d+)?|[-+*/^r()]~';