# Maputil
Package maputil includes some functions to manipulate map.
# Source:
# Example:
import (
"github.com/duke-git/lancet/v2/maputil"
)
# Documentation
# ForEach
Executes iteratee funcation for every key and value pair in map.
Signature:
func ForEach[K comparable, V any](m map[K]V, iteratee func(key K, value V))
Example:
package main
import (
"fmt"
"github.com/duke-git/lancet/v2/maputil"
)
func main() {
m := map[string]int{
"a": 1,
"b": 2,
"c": 3,
"d": 4,
}
var sum int
maputil.ForEach(m, func(_ string, value int) {
sum += value
})
fmt.Println(sum) // 10
}
# Filter
Iterates over map, return a new map contains all key and value pairs pass the predicate function.
Signature:
func Filter[K comparable, V any](m map[K]V, predicate func(key K, value V) bool) map[K]V
Example:
package main
import (
"fmt"
"github.com/duke-git/lancet/v2/maputil"
)
func main() {
m := map[string]int{
"a": 1,
"b": 2,
"c": 3,
"d": 4,
"e": 5,
}
isEven := func(_ string, value int) bool {
return value%2 == 0
}
maputil.Filter(m, func(_ string, value int) {
sum += value
})
res := maputil.Filter(m, isEven)
fmt.Println(res) // map[string]int{"b": 2, "d": 4,}
}
# Intersect
Iterates over maps, return a new map of key and value pairs in all given maps.
Signature:
func Intersect[K comparable, V any](maps ...map[K]V) map[K]V
Example:
package main
import (
"fmt"
"github.com/duke-git/lancet/v2/maputil"
)
func main() {
m1 := map[string]int{
"a": 1,
"b": 2,
"c": 3,
}
m2 := map[string]int{
"a": 1,
"b": 2,
"c": 6,
"d": 7,
}
m3 := map[string]int{
"a": 1,
"b": 9,
"e": 9,
}
fmt.Println(maputil.Intersect(m1)) // map[string]int{"a": 1, "b": 2, "c": 3}
fmt.Println(maputil.Intersect(m1, m2)) // map[string]int{"a": 1, "b": 2}
fmt.Println(maputil.Intersect(m1, m2, m3)) // map[string]int{"a": 1}
}
# Keys
Returns a slice of the map's keys.
Signature:
func Keys[K comparable, V any](m map[K]V) []K
Example:
package main
import (
"fmt"
"github.com/duke-git/lancet/v2/maputil"
)
func main() {
m := map[int]string{
1: "a",
2: "a",
3: "b",
4: "c",
5: "d",
}
keys := maputil.Keys(m)
sort.Ints(keys)
fmt.Println(keys) // []int{1, 2, 3, 4, 5}
}
# Merge
Merge maps, next key will overwrite previous key.
Signature:
func Merge[K comparable, V any](maps ...map[K]V) map[K]V
Example:
package main
import (
"fmt"
"github.com/duke-git/lancet/v2/maputil"
)
func main() {
m1 := map[int]string{
1: "a",
2: "b",
}
m2 := map[int]string{
1: "1",
3: "2",
}
fmt.Println(maputil.Merge(m1, m2)) // map[int]string{1:"1", 2:"b", 3:"2",}
}
# Minus
Creates an map of whose key in mapA but not in mapB.
Signature:
func Minus[K comparable, V any](mapA, mapB map[K]V) map[K]V
Example:
package main
import (
"fmt"
"github.com/duke-git/lancet/v2/maputil"
)
func main() {
m1 := map[string]int{
"a": 1,
"b": 2,
"c": 3,
}
m2 := map[string]int{
"a": 11,
"b": 22,
"d": 33,
}
fmt.Println(maputil.Minus(m1, m2)) //map[string]int{"c": 3}
}
# Values
Returns a slice of the map's values.
Signature:
func Values[K comparable, V any](m map[K]V) []V
Example:
package main
import (
"fmt"
"github.com/duke-git/lancet/v2/maputil"
)
func main() {
m := map[int]string{
1: "a",
2: "a",
3: "b",
4: "c",
5: "d",
}
values := maputil.Values(m)
sort.Strings(values)
fmt.Println(values) // []string{"a", "a", "b", "c", "d"}
}
# IsDisjoint
Checks two maps are disjoint if they have no keys in common
Signature:
func IsDisjoint[K comparable, V any](mapA, mapB map[K]V) bool
Example:
package main
import (
"fmt"
"github.com/duke-git/lancet/v2/maputil"
)
func main() {
m1 := map[int]string{
1: "a",
2: "a",
3: "b",
4: "c",
5: "d",
}
m2 := map[int]string{
1: "a",
2: "a",
3: "b",
4: "c",
5: "d",
}
m3 := map[int]string{
6: "a",
}
ok := maputil.IsDisjoint(m2, m1)
fmt.Println(ok) // false
ok = maputil.IsDisjoint(m2, m3)
fmt.Println(ok) // true
}