Skip to content

CountBy

func CountBy[T any, K comparable](slice []T, keySelector func(T) K) map[K]int

CountBy counts the occurrences of each key extracted using the keySelector function. Returns a map where keys are the extracted keys and values are the counts.

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

import (
    "fmt"

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

func main() {
    words := []string{"apple", "banana", "apricot", "blueberry", "avocado"}

    // Count words by first letter
    counts := sliceutils.CountBy(words, func(word string) rune {
        return rune(word[0])
    })

    fmt.Printf("%v\n", counts)
    // map[97:3 98:2] (a=3, b=2)
}