Tables operations

[claus707]

Hello to every one!
I have 3 tables
tbl_1, tbl_2, tbl_3.
The first table tbl_1 always has much more items that tbl_2 and tbl_3.
My issue is that I want to remove all tbl_1 items that are on tbl_2 and the result should be a new table tbl_3.

Example:
tbl_1 ={"1", "2", "3", "4", "5"};
tbl_2 ={"1", "5"};
The result should be:
tbl_3 ={"2", "3", "4"};

[sidiamur]

a= {"1", "2", "3", "4", "5"};
b= {"1", "5"};
count = Table.Count(b);
for i,f in pairs  (b) do
  for t,d in pairs  (a) do
        if  f == d then      
          Table.Remove(a, t);
        end
  end
end
for n, k in pairs(a) do
  Input.SetText("Input1", k..","..Input.GetText("Input1"));
end 

[claus707]

Thank you for the reply.
Your code helped me a lot!

My issue is : the a table is the list of the ids of workers on a database table and the b table is the list of ids of some workers that have not worked that day and should be removed...
The code that you wrote modifies the main table a, so after every request the list of total workers should be re generated(a query on the database will be made and may slow the app), but at least for now I have a solution.

[startup]

ok let us make a modification

a= {"1", "2", "3", "4", "5"};
b= {"1", "5"};
c=a  --let us copy the main table to play free with the new one !!
count = Table.Count(b);
for i,f in pairs  (b) do
  for t,d in pairs  (c) do
        if  f == d then      
          Table.Remove(c, t);
        end
  end
end
for n, k in pairs(c) do
  Input.SetText("Input1", k..","..Input.GetText("Input1"));
end 

now we will not effect table a
is this solve ??

[claus707]

Thank you both

[reteset]

My issue is : the a table is the list of the ids of workers on a database table and the b table is the list of ids of some workers that have not worked that day and should be removed...
The code that you wrote modifies the main table a, so after every request the list of total workers should be re generated(a query on the database will be made and may slow the app), but at least for now I have a solution.

if you load table 'tbl_1' from a database query
why do not you do this task on that database query which is the most efficient way

you can make it with a sql query something like below

select * from table_a left join table_b on table_a.worker_id = table_b.worker_id where table_b.worker_id is null;

so , result of this query will be 'tbl_3' and you do not have to make another query for 'tbl_2' as well

and there is no need to loop through those two Lua tables

[startup]

if you load table 'tbl_1' from a database query
why do not you do this task on that database query which is the most efficient way

you can make it with a sql query something like below

select * from table_a left join table_b on table_a.worker_id = table_b.worker_id where table_b.worker_id is null;

so , result of this query will be 'tbl_3' and you do not have to make another query for 'tbl_2' as well

and there is no need to loop through those two Lua tables

wonderful !!
a master solution
thanks a lot

very powerful solution !!