Question

Please help me to write a function to find difference of two lists including duplicate elements. Lists are not equal lengths.

q)l1:1 1 2 3 3 4 4 5 6 7
q)l2: 1 1 2 4 5 6
q)l1 except l2
3 3 7      /4 is missing in result
/expected result : 3 3 4 7

Answer 1

你们可以尝试这样的事情:

q){$[any found:x in y;x _:first where found;x]}/[l1;l2]
3 3 4 7

它通过第2号中的物品,看看是否有1英里的物品,并放下。

Answer 2

<代码>组功能可在此查阅。

{
  e: (count each group x) - (count each group y); 
  e: (where e>0)#e;
  raze (value e)# (key e)
}

On the 1st step we check how many numbers are in both lists and subtract counts. Then we keep only numbers with positive counts and convert number->count dictionary into desired list.

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