Skip to content

MapKeys

func MapKeys[K comparable, V any, R comparable](mapInstance map[K]V, mapper func(key K, value V) R) map[R]V

MapKeys transforms map keys using a mapper function, returning a new map with transformed keys. If the mapper produces duplicate keys, later values will overwrite earlier ones.

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
package main

import (
    "fmt"
    "strings"

    "github.com/Goldziher/go-utils/maputils"
)

func main() {
    data := map[string]int{
        "apple":  5,
        "BANANA": 3,
        "Cherry": 8,
    }

    // Normalize keys to lowercase
    normalized := maputils.MapKeys(data, func(k string, v int) string {
        return strings.ToLower(k)
    })

    fmt.Printf("%v\n", normalized)
    // map[apple:5 banana:3 cherry:8]
}