PHP正則表達式意外的比賽

Question

我在我的PHP代碼中的正則表達式應該每個數字和所有的「運營商」 +匹配 - */^ R（）我的正則表達式看起來像這樣

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

和測試時以字符串preg_match_all($expression,"2+2",$results)它給我回

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] => '' 
     ) 

) 

當（如果它的工作原理右）我應該得到這個

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，它返回類似行爲對於所有的運營商，它似乎忽略的數字完全

注意，我確實需要單獨的捕捉組，所以我有不同的匹配指標。對於每個結果

Answer 1

你可以簡單地做到這一點：

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