Several methods for map deduplication in golang

Go language is a strongly typed, static language, known as the "C language of the Internet era". In the standard library of the Go language, map is a very commonly used data structure, often used to store key-value pairs. Map can be created using the make function and provides rich operation methods. However, as the number of elements in the map increases, the memory occupied by it will become larger and larger. If not controlled, it may cause the program's memory usage to be too high. This article will introduce several methods to implement golang map deduplication to help you better control program memory.

Method 1: Traverse and count

To delete specified elements in the map, you need to use the built-in delete function. However, for situations where all elements in the map need to be deduplicated, we can achieve map deduplication by traversing the map and counting the number of elements.

The specific process is as follows:

1. Define a map of type map[string]int;
2. Traverse the original map and count the number of occurrences of each element;
3. Construct a new map and put elements with an occurrence count of 1 into the map;
4. Return the new map.

The sample code is as follows:

func removeDuplicate(m map[string]string) map[string]string {
    counts := make(map[string]int)
    for _, v := range m {
        counts[v] += 1
    }
    res := make(map[string]string)
    for k, v := range m {
        if counts[v] == 1 {
            res[k] = v
        }
    }
    return res
}

Method 2: Use slice as auxiliary storage

Another method of golang map deduplication is to use slice as auxiliary storage. The process is as follows:

1. Define a map of type map[string]bool;
2. Traverse the original map and store all key-value pairs in the map into the auxiliary map;
3. Construct a new slice and store all the keys in the auxiliary map into the slice;
4. Return the new slice.

The sample code is as follows:

func removeDuplicate(m map[string]string) []string {
    res := make([]string, 0, len(m))
    temp := make(map[string]bool)
    for _, v := range m {
        if _, ok := temp[v]; !ok {
            temp[v] = true
            res = append(res, v)
        }
    }
    return res
}

Method 3: Using struct for filtering

Using struct for filtering is also one of the ways to achieve map deduplication. The specific steps are as follows:

1. Define a struct, each element contains two attributes key and value;
2. Define a map of type map[string]struct;
3. Traverse the original map, use the element value as the key, and construct a new map[string]struct;
4. Return the new map.

The sample code is as follows:

func removeDuplicate(m map[string]string) map[string]struct{} {
    res := make(map[string]struct{}, len(m))
    for _, v := range m {
        res[v] = struct{}{}
    }
    return res
}

Summary

The above are three methods to implement golang map deduplication, namely traversing and counting, and using slice as auxiliary storage and use struct for filtering. When using map, pay attention to controlling the number of elements to avoid excessive memory usage and affecting program performance. Hope this article is helpful to you.

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