maps

Documentation

Overview

Package maps defines various functions useful with maps of any type.

Index

• func Clone[M ~map[K]V, K comparable, V any](m M) M
• func Copy[M1 ~map[K]V, M2 ~map[K]V, K comparable, V any](dst M1, src M2)
• func DeleteFunc[M ~map[K]V, K comparable, V any](m M, del func(K, V) bool)
• func Equal[M1, M2 ~map[K]V, K, V comparable](m1 M1, m2 M2) bool
• func EqualFunc[M1 ~map[K]V1, M2 ~map[K]V2, K comparable, V1, V2 any](m1 M1, m2 M2, eq func(V1, V2) bool) bool
• func Keys[M ~map[K]V, K comparable, V any](m M) []K
• func Values[M ~map[K]V, K comparable, V any](m M) []V

Examples

• DeleteFunc
• EqualFunc

Functions

func Clone

func Clone[M ~map[K]V, K comparable, V any](m M) M

Clone returns a copy of m. This is a shallow clone: the new keys and values are set using ordinary assignment.

func Copy

func Copy[M1 ~map[K]V, M2 ~map[K]V, K comparable, V any](dst M1, src M2)

Copy copies all key/value pairs in src adding them to dst. When a key in src is already present in dst, the value in dst will be overwritten by the value associated with the key in src.

func DeleteFunc

func DeleteFunc[M ~map[K]V, K comparable, V any](m M, del func(K, V) bool)

DeleteFunc deletes any key/value pairs from m for which del returns true.

Example

package main

import (
	"fmt"
	"maps"
)

func main() {
	m := map[string]int{
		"one":   1,
		"two":   2,
		"three": 3,
		"four":  4,
	}
	maps.DeleteFunc(m, func(k string, v int) bool {
		return v%2 != 0 // delete odd values
	})
	fmt.Println(m)
}

Output:

map[four:4 two:2]

func Equal

func Equal[M1, M2 ~map[K]V, K, V comparable](m1 M1, m2 M2) bool

Equal reports whether two maps contain the same key/value pairs. Values are compared using ==.

func EqualFunc

func EqualFunc[M1 ~map[K]V1, M2 ~map[K]V2, K comparable, V1, V2 any](m1 M1, m2 M2, eq func(V1, V2) bool) bool

EqualFunc is like Equal, but compares values using eq. Keys are still compared with ==.

Example

package main

import (
	"fmt"
	"maps"
	"strings"
)

func main() {
	m1 := map[int]string{
		1:    "one",
		10:   "Ten",
		1000: "THOUSAND",
	}
	m2 := map[int][]byte{
		1:    []byte("One"),
		10:   []byte("Ten"),
		1000: []byte("Thousand"),
	}
	eq := maps.EqualFunc(m1, m2, func(v1 string, v2 []byte) bool {
		return strings.ToLower(v1) == strings.ToLower(string(v2))
	})
	fmt.Println(eq)
}

Output:

true

func Keys

func Keys[M ~map[K]V, K comparable, V any](m M) []K

Keys returns the keys of the map m. The keys will be in an indeterminate order.

func Values

func Values[M ~map[K]V, K comparable, V any](m M) []V

Values returns the values of the map m. The values will be in an indeterminate order.