How do I group items by key using a map?

This example demonstrates how to group items by a specific key using a map in Go. We create a slice of items, then use a map to group those items by a designated key.

Go, grouping, map, example, programming


        package main

        import (
            "fmt"
        )

        func main() {
            items := []struct {
                Key   string
                Value string
            }{
                {"fruit", "apple"},
                {"fruit", "banana"},
                {"vegetable", "carrot"},
                {"fruit", "date"},
                {"vegetable", "eggplant"},
            }

            grouped := make(map[string][]string)

            for _, item := range items {
                grouped[item.Key] = append(grouped[item.Key], item.Value)
            }

            fmt.Println(grouped)
        }