1 // Copyright 2021 The Go Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style
3 // license that can be found in the LICENSE file.
5 // Package maps defines various functions useful with maps of any type.
8 // Keys returns the keys of the map m.
9 // The keys will be in an indeterminate order.
10 func Keys[M ~map[K]V, K comparable, V any](m M) []K {
11 r := make([]K, 0, len(m))
18 // Values returns the values of the map m.
19 // The values will be in an indeterminate order.
20 func Values[M ~map[K]V, K comparable, V any](m M) []V {
21 r := make([]V, 0, len(m))
28 // Equal reports whether two maps contain the same key/value pairs.
29 // Values are compared using ==.
30 func Equal[M1, M2 ~map[K]V, K, V comparable](m1 M1, m2 M2) bool {
31 if len(m1) != len(m2) {
34 for k, v1 := range m1 {
35 if v2, ok := m2[k]; !ok || v1 != v2 {
42 // EqualFunc is like Equal, but compares values using eq.
43 // Keys are still compared with ==.
44 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 {
45 if len(m1) != len(m2) {
48 for k, v1 := range m1 {
49 if v2, ok := m2[k]; !ok || !eq(v1, v2) {
56 // Clone returns a copy of m. This is a shallow clone:
57 // the new keys and values are set using ordinary assignment.
58 func Clone[M ~map[K]V, K comparable, V any](m M) M {
59 // Preserve nil in case it matters.
70 // Copy copies all key/value pairs in src adding them to dst.
71 // When a key in src is already present in dst,
72 // the value in dst will be overwritten by the value associated
73 // with the key in src.
74 func Copy[M1 ~map[K]V, M2 ~map[K]V, K comparable, V any](dst M1, src M2) {
75 for k, v := range src {
80 // DeleteFunc deletes any key/value pairs from m for which del returns true.
81 func DeleteFunc[M ~map[K]V, K comparable, V any](m M, del func(K, V) bool) {