Remove duplicate from response-CodePudding

I have the following task: I'm making loop that doing requests to server and recieving a value, for example it is a slice of ints. Then I need to pass this slice of ints to another task. The thing is that sometime I recieve duplicate value from server, for example:

resp1 := []int{1,2,3,4} > do some things
resp2 := []int{3,4,5,6} > do some things

But I want to pass only NEW values from response to next task

resp1 := []int{1,2,3,4} > pass 1,2,3,4
resp2 := []int{3,4,5,6} > pass 5,6

Is there any solution to avoid / "clean up" duplicates from value?

CodePudding user response：

The general idea would be to maintain a global ~~slice~~ map (as suggested by mkopriva in the comments) which would memorize any value you are passing to your other task.

Build also a new slice which would:

test for each value 'x' (of respx) in the global map:
- if present, your new slice would not include that value
- if absent, your new slice would include that value (and an empty struct value would be added to your global map, with 'x' as key)
pass the new slice (with only new values, never passed before) to the new task

The point is: your current task is stateful and need to maintain a state between each call.

You will need some kind of global variable and/or singleton, something which will span the life of the execution of your program.
mkopriva also mentions the "visited pattern" as implementation examples.

CodePudding user response：

You can store the values you have already seen in a map and using that you can generate unique values each time you get a response. A function to get unique response can be like this :

func getUniqueResponse(curResp []int, seen map[int]bool) []int {
    var resp []int
    for _, num := range curResp {
        if !seen[num] {
            seen[num] = true
            resp = append(resp, num)
        }
    }
    return resp
}

You can declare a map[int]bool and pass that map along with slice and receive a unique slice.

seen := make(map[int]bool)
resp := []int{1, 2, 3, 4}
uniqueResp := getUniqueResponse(resp, seen)
// Do other work with unique Response
resp = []int{3, 4, 5, 6}
uniqueResp = getUniqueResponse(resp, seen)
// Do other work with unique Response