lua里面求int数组的union,diff,inter,distinct 方法实现

 --利用lua中的table是哈希表这一点进行计算
 function lua_distinct_union (union_t1,union_t2)
     if(union_t2==nil) then
         union_t2={};
     end;
     local result={};
     for k,v in pairs(union_t1) do
         result[v]=v;
     end;
     for k,v in pairs(union_t2) do
         if result[v] ==nil then
             result[v]=v;
         end;
     end;
     union_t1=nil;
     union_t2=nil;
     return result;
 end;

 function lua_distinct (distinct_t)
     local result={};
     for k,v in pairs(distinct_t) do
         if(result[v]==nil) then
         result[v]=v;
     end;
 end;
 distinct_t=nil;
 return result;
 end;

 function lua_distinct_diff(diff_t1,diff_t2) local result={};
     for k,v in pairs(diff_t1) do
         if(result[v]==nil) then
         result[v]=v;
     end;
 end;

 for k,v in pairs(diff_t2) do
     if(result[v]~=nil) then
     table.remove(result,v);
 end;
 end;
 diff_t1=nil;
 diff_t2=nil;
 return result;
 end;

 function lua_distinct_inter (inter_t1,inter_t2)
     if inter_t1==nil and inter_t2~=nil then
         return lua_distinct(inter_t2);
     end;
     if inter_t1~=nil and inter_t2==nil then
         return lua_distinct(inter_t1);
     end;
     local temp1={};
     local temp2={};
     local result={};
     local num1=;
     local num2=;
     for k,v in pairs(inter_t1) do
         if(temp1[v]==nil) then
             temp1[v]=v;
             num1=num1+;
         end;
     end;
     for k,v in pairs(inter_t2) do
         if(temp2[v]==nil) then
             temp2[v]=v;
             num2=num2+;
         end;
     end;
     inter_t1=nil;
     inter_t2=nil;
     if num1<num2 then
         for k,v in pairs(temp1) do
             if temp2[k]~=nil then
                 result[k]=temp1[k];
             end;
         end;
     else
         for k,v in pairs(temp2) do
             if temp2[k]~=nil then
                 result[k]=temp1[k];
             end;
         end;
     end;
     temp1=nil;
     temp2=nil;
     return result;
 end;

 function lua_distinct_union_multiply(tablesneedunion)
     if(tablesneedunion==nil or #(tablesneedunion)==) then
         error('lua_distinct_diff_Multiply传入参数为空');
     end;
     local result=tablesneedunion[];
     if #(tablesneedunion)== then
         return lua_distinct_union(result,nil);
     end;
     for i=,#(tablesneedunion) do
         local tmp=tablesneedunion[i];
         result=lua_distinct_union(tmp,result);
     end;
     tablesneedunion=nil;
     return result;
 end;

 function lua_distinct_inter_multiply(tablesneedinter)
     if(tablesneedinter==nil or #(tablesneedinter)==) then
     error('lua_distinct_inter_multiply传入参数为空');
     end;
     local result=tablesneedinter[];
     if #(tablesneedinter)== then
         return lua_distinct_inter(result,nil);
     end;
     for i=,#(tablesneedinter) do
         local tmp=tablesneedinter[i];
         result=lua_distinct_inter(tmp,result);
         if  #(result)== then
             break;
         end;
     end;
     tablesneedinter=nil;
     return result;
 end;

 function getidsfromkeyvaluepair(keyvaluepair)
     local result={};
     if(keyvaluepair==nil) then
         return result;
     end;
     local num=;
     for k,v in pairs(keyvaluepair) do
         result[num]=v;
         num=num+;
     end;
     return result;
 end;

 function lua_getfinalids(structs)
     if #(structs)== then
         return getidsfromkeyvaluepair(temptable);
     end;
     local temptable=structs[].temptable;
     for i=,#(structs) do
         local tmp2=structs[i].temptable;
         if structs[i-].flag== then
             temptable=lua_distinct_union(temptable,tmp2);
         else
             temptable=lua_distinct_inter(temptable,tmp2);
         end;
     end;
     return getidsfromkeyvaluepair(temptable);
 end;

 function lua_sortandtake(tableneedsort,takecount,isasc)
     if isasc==true then
         table.sort(tableneedsort);
     else
         table.sort(tableneedsort,function(a,b) return a>b end );
     end;
     local result={};
     for i= ,takecount do
         result[i]=tableneedsort[i];
     end;
     return result;
 end;