如何计算一般数组中的每个唯一元素

Good day.

Code:

array(4) { 
    [0]=> array(1) { 
          [0]=> array(3) { 
               [0]=> string(11) "art_7880" [1]=> string(1) "1" [2]=> int(2950) 
          }
          [1]=> array(3) { 
               [0]=> string(8) "art_7880" [1]=> string(1) "1" [2]=> int(2955)  
          } 
          [2]=> array(3) { 
               [0]=> string(8) "art_7880" [1]=> string(1) "1" [2]=> int(1335)  
          }
          [3]=> array(3) { 
               [0]=> string(8) "art_7883" [1]=> string(1) "1" [2]=> int(4335)  
          }
}
array(4) { 
    [0]=> array