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25 KiB
25 KiB
Maputil
Package maputil includes some functions to manipulate map.
Source:
Example:
import (
"github.com/duke-git/lancet/v2/maputil"
)
Index
- MapTo
- ForEach
- Filter
- FilterByKeys
- FilterByValues
- OmitBy
- OmitByKeys
- OmitByValues
- Intersect
- Keys
- Values
- KeysBy
- ValuesBy
- MapKeys
- MapValues
- Entries
- FromEntries
- Transform
- Merge
- Minus
- IsDisjoint
- HasKey
- NewConcurrentMap
- ConcurrentMap_Get
- ConcurrentMap_Set
- ConcurrentMap_GetOrSet
- ConcurrentMap_Delete
- ConcurrentMap_GetAndDelete
- ConcurrentMap_Has
- ConcurrentMap_Range
Documentation
MapTo
Rry to map any interface to struct or base type.
Signature:
func MapTo(src any, dst any) error
Example:Run
package main
import (
"fmt"
"github.com/duke-git/lancet/v2/maputil"
)
func main() {
type (
Person struct {
Name string `json:"name"`
Age int `json:"age"`
Phone string `json:"phone"`
Addr Address `json:"address"`
}
Address struct {
Street string `json:"street"`
Number int `json:"number"`
}
)
personInfo := map[string]interface{}{
"name": "Nothin",
"age": 28,
"phone": "123456789",
"address": map[string]interface{}{
"street": "test",
"number": 1,
},
}
var p Person
err := MapTo(personInfo, &p)
fmt.Println(err)
fmt.Println(p)
// Output:
// <nil>
// {Nothin 28 123456789 {test 1}}
}
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:Run
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)
// Output:
// 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:Run
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
})
result := maputil.Filter(m, isEven)
fmt.Println(result)
// Output:
// map[b:2 d:4]
}
FilterByKeys
Iterates over map, return a new map whose keys are all given keys.
Signature:
func FilterByKeys[K comparable, V any](m map[K]V, keys []K) map[K]V
Example:Run
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,
}
result := maputil.FilterByKeys(m, []string{"a", "b"})
fmt.Println(result)
// Output:
// map[a:1 b:2]
}
FilterByValues
Iterates over map, return a new map whose values are all given values.
Signature:
func FilterByValues[K comparable, V comparable](m map[K]V, values []V) map[K]V
Example:Run
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,
}
result := maputil.FilterByValues(m, []int{3, 4})
fmt.Println(result)
// Output:
// map[c:3 d:4]
}
OmitBy
OmitBy is the opposite of Filter, removes all the map elements for which the predicate function returns true.
Signature:
func OmitBy[K comparable, V any](m map[K]V, predicate func(key K, value V) bool) map[K]V
Example:Run
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
}
result := maputil.OmitBy(m, isEven)
fmt.Println(result)
// Output:
// map[a:1 c:3 e:5]
}
OmitByKeys
The opposite of FilterByKeys, extracts all the map elements which keys are not omitted.
Signature:
func OmitByKeys[K comparable, V any](m map[K]V, keys []K) map[K]V
Example:Run
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,
}
result := maputil.OmitByKeys(m, []string{"a", "b"})
fmt.Println(result)
// Output:
// map[c:3 d:4 e:5]
}
OmitByValues
The opposite of FilterByValues. remov all elements whose value are in the give slice.
Signature:
func OmitByValues[K comparable, V comparable](m map[K]V, values []V) map[K]V
Example:Run
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,
}
result := maputil.OmitByValues(m, []int{4, 5})
fmt.Println(result)
// Output:
// map[a:1 b:2 c:3]
}
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:Run
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,
}
result1 := maputil.Intersect(m1)
result2 := maputil.Intersect(m1, m2)
result3 := maputil.Intersect(m1, m2, m3)
fmt.Println(result1)
fmt.Println(result2)
fmt.Println(result3)
// Output:
// map[a:1 b:2 c:3]
// map[a:1 b:2]
// map[a:1]
}
Keys
Returns a slice of the map's keys.
Signature:
func Keys[K comparable, V any](m map[K]V) []K
Example:Run
package main
import (
"fmt"
"sort"
"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)
// Output:
// [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:Run
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",
}
result := maputil.Merge(m1, m2)
fmt.Println(result)
// Output:
// map[1:c 2:b 3:d]
}
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:Run
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,
}
result := maputil.Minus(m1, m2)
fmt.Println(result)
// Output:
// map[c:3]
}
Values
Returns a slice of the map's values.
Signature:
func Values[K comparable, V any](m map[K]V) []V
Example:Run
package main
import (
"fmt"
"sort"
"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)
// Output:
// [a a b c d]
}
KeysBy
Creates a slice whose element is the result of function mapper invoked by every map's key.
Signature:
func KeysBy[K comparable, V any, T any](m map[K]V, mapper func(item K) T) []T
Example:Run
package main
import (
"fmt"
"sort"
"github.com/duke-git/lancet/v2/maputil"
)
func main() {
m := map[int]string{
1: "a",
2: "a",
3: "b",
}
keys := maputil.KeysBy(m, func(n int) int {
return n + 1
})
sort.Ints(keys)
fmt.Println(keys)
// Output:
// [2 3 4]
}
ValuesBy
Creates a slice whose element is the result of function mapper invoked by every map's value.
Signature:
func ValuesBy[K comparable, V any, T any](m map[K]V, mapper func(item V) T) []T
Example:Run
package main
import (
"fmt"
"sort"
"github.com/duke-git/lancet/v2/maputil"
)
func main() {
m := map[int]string{
1: "a",
2: "b",
3: "c",
}
values := maputil.ValuesBy(m, func(v string) string {
switch v {
case "a":
return "a-1"
case "b":
return "b-2"
case "c":
return "c-3"
default:
return ""
}
})
sort.Strings(values)
fmt.Println(values)
// Output:
// [a-1 b-2 c-3]
}
MapKeys
Transforms a map to other type map by manipulating it's keys.
Signature:
func MapKeys[K comparable, V any, T comparable](m map[K]V, iteratee func(key K, value V) T) map[T]V
Example:Run
package main
import (
"fmt"
"strconv"
"github.com/duke-git/lancet/v2/maputil"
)
func main() {
m := map[int]string{
1: "a",
2: "b",
3: "c",
}
result := maputil.MapKeys(m, func(k int, _ string) string {
return strconv.Itoa(k)
})
fmt.Println(result)
// Output:
// map[1:a 2:b 3:c]
}
MapValues
Transforms a map to other type map by manipulating it's values.
Signature:
func MapValues[K comparable, V any, T any](m map[K]V, iteratee func(key K, value V) T) map[K]T
Example:Run
package main
import (
"fmt"
"strconv"
"github.com/duke-git/lancet/v2/maputil"
)
func main() {
m := map[int]string{
1: "a",
2: "b",
3: "c",
}
result := maputil.MapValues(m, func(k int, v string) string {
return v + strconv.Itoa(k)
})
fmt.Println(result)
// Output:
// map[1:a1 2:b2 3:c3]
}
Entry
Transforms a map into array of key/value pairs.
Signature:
type Entry[K comparable, V any] struct {
Key K
Value V
}
func Entries[K comparable, V any](m map[K]V) []Entry[K, V]
Example:Run
package main
import (
"fmt"
"sort"
"github.com/duke-git/lancet/v2/maputil"
)
func main() {
m := map[string]int{
"a": 1,
"b": 2,
"c": 3,
}
result := maputil.Entries(m)
sort.Slice(result, func(i, j int) bool {
return result[i].Value < result[j].Value
})
fmt.Println(result)
// Output:
// [{a 1} {b 2} {c 3}]
}
FromEntries
Creates a map based on a slice of key/value pairs.
Signature:
type Entry[K comparable, V any] struct {
Key K
Value V
}
func FromEntries[K comparable, V any](entries []Entry[K, V]) map[K]V
Example:Run
package main
import (
"fmt"
"github.com/duke-git/lancet/v2/maputil"
)
func main() {
result := maputil.FromEntries([]Entry[string, int]{
{Key: "a", Value: 1},
{Key: "b", Value: 2},
{Key: "c", Value: 3},
})
fmt.Println(result)
// Output:
// map[a:1 b:2 c:3]
}
Transform
Transform a map to another type map.
Signature:
func Transform[K1 comparable, V1 any, K2 comparable, V2 any](m map[K1]V1, iteratee func(key K1, value V1) (K2, V2)) map[K2]V2
Example:Run
package main
import (
"fmt"
"strconv"
"github.com/duke-git/lancet/v2/maputil"
)
func main() {
m := map[string]int{
"a": 1,
"b": 2,
"c": 3,
}
result := Transform(m, func(k string, v int) (string, string) {
return k, strconv.Itoa(v)
})
fmt.Println(result)
// Output:
// map[a:1 b:2 c:3]
}
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:Run
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{
"d": 22,
}
m3 := map[string]int{
"a": 22,
}
result1 := maputil.IsDisjoint(m1, m2)
result2 := maputil.IsDisjoint(m1, m3)
fmt.Println(result1)
fmt.Println(result2)
// Output:
// true
// false
}
HasKey
Checks if map has key or not. This function is used to replace the following boilerplate code:
_, haskey := amap["baz"];
if haskey {
fmt.Println("map has key baz")
}
Signature:
func HasKey[K comparable, V any](m map[K]V, key K) bool
Example:Run
package main
import (
"fmt"
"github.com/duke-git/lancet/v2/maputil"
)
func main() {
m := map[string]int{
"a": 1,
"b": 2,
}
result1 := maputil.HasKey(m, "a")
result2 := maputil.HasKey(m, "c")
fmt.Println(result1)
fmt.Println(result2)
// Output:
// true
// false
}
NewConcurrentMap
ConcurrentMap is like map, but is safe for concurrent use by multiple goroutines.
Signature:
// NewConcurrentMap create a ConcurrentMap with specific shard count.
func NewConcurrentMap[K comparable, V any](shardCount int) *ConcurrentMap[K, V]
Example:Run
package main
import (
"fmt"
"github.com/duke-git/lancet/v2/maputil"
)
func main() {
// create a ConcurrentMap whose key type is string, value type is int
cm := maputil.NewConcurrentMap[string, int](100)
}
ConcurrentMap_Set
Set the value for a key.
Signature:
func (cm *ConcurrentMap[K, V]) Set(key K, value V)
Example:Run
package main
import (
"fmt"
"github.com/duke-git/lancet/v2/maputil"
)
func main() {
cm := maputil.NewConcurrentMap[string, int](100)
var wg1 sync.WaitGroup
wg1.Add(5)
for i := 0; i < 5; i++ {
go func(n int) {
cm.Set(fmt.Sprintf("%d", n), n)
wg1.Done()
}(i)
}
wg1.Wait()
var wg2 sync.WaitGroup
wg2.Add(5)
for j := 0; j < 5; j++ {
go func(n int) {
val, ok := cm.Get(fmt.Sprintf("%d", n))
fmt.Println(val, ok)
wg2.Done()
}(j)
}
wg2.Wait()
// output: (order may change)
// 1 true
// 3 true
// 2 true
// 0 true
// 4 true
}
ConcurrentMap_Get
Get the value stored in the map for a key, or nil if no.
Signature:
func (cm *ConcurrentMap[K, V]) Get(key K) (V, bool)
Example:Run
package main
import (
"fmt"
"github.com/duke-git/lancet/v2/maputil"
)
func main() {
cm := maputil.NewConcurrentMap[string, int](100)
var wg1 sync.WaitGroup
wg1.Add(5)
for i := 0; i < 5; i++ {
go func(n int) {
cm.Set(fmt.Sprintf("%d", n), n)
wg1.Done()
}(i)
}
wg1.Wait()
var wg2 sync.WaitGroup
wg2.Add(5)
for j := 0; j < 5; j++ {
go func(n int) {
val, ok := cm.Get(fmt.Sprintf("%d", n))
fmt.Println(val, ok)
wg2.Done()
}(j)
}
wg2.Wait()
// output: (order may change)
// 1 true
// 3 true
// 2 true
// 0 true
// 4 true
}
ConcurrentMap_GetOrSet
Returns the existing value for the key if present. Otherwise, it sets and returns the given value.
Signature:
func (cm *ConcurrentMap[K, V]) GetOrSet(key K, value V) (actual V, ok bool)
Example:Run
package main
import (
"fmt"
"github.com/duke-git/lancet/v2/maputil"
)
func main() {
cm := maputil.NewConcurrentMap[string, int](100)
var wg sync.WaitGroup
wg.Add(5)
for i := 0; i < 5; i++ {
go func(n int) {
val, ok := cm.GetOrSet(fmt.Sprintf("%d", n), n)
fmt.Println(val, ok)
wg.Done()
}(i)
}
wg.Wait()
// output: (order may change)
// 1 false
// 3 false
// 2 false
// 0 false
// 4 false
}
ConcurrentMap_Delete
Delete the value for a key.
Signature:
func (cm *ConcurrentMap[K, V]) Delete(key K)
Example:Run
package main
import (
"fmt"
"github.com/duke-git/lancet/v2/maputil"
)
func main() {
cm := maputil.NewConcurrentMap[string, int](100)
var wg1 sync.WaitGroup
wg1.Add(5)
for i := 0; i < 5; i++ {
go func(n int) {
cm.Set(fmt.Sprintf("%d", n), n)
wg1.Done()
}(i)
}
wg1.Wait()
var wg2 sync.WaitGroup
wg2.Add(5)
for j := 0; j < 5; j++ {
go func(n int) {
cm.Delete(fmt.Sprintf("%d", n))
wg2.Done()
}(j)
}
wg2.Wait()
}
ConcurrentMap_GetAndDelete
Returns the existing value for the key if present and then delete the value for the key. Otherwise, do nothing, just return false.
Signature:
func (cm *ConcurrentMap[K, V]) GetAndDelete(key K) (actual V, ok bool)
Example:Run
package main
import (
"fmt"
"github.com/duke-git/lancet/v2/maputil"
)
func main() {
cm := maputil.NewConcurrentMap[string, int](100)
var wg1 sync.WaitGroup
wg1.Add(5)
for i := 0; i < 5; i++ {
go func(n int) {
cm.Set(fmt.Sprintf("%d", n), n)
wg1.Done()
}(i)
}
wg1.Wait()
var wg2 sync.WaitGroup
wg2.Add(5)
for j := 0; j < 5; j++ {
go func(n int) {
val, ok := cm.GetAndDelete(fmt.Sprintf("%d", n))
fmt.Println(val, ok) //n, true
_, ok = cm.Get(fmt.Sprintf("%d", n))
fmt.Println(val, ok) //false
wg2.Done()
}(j)
}
wg2.Wait()
}
ConcurrentMap_Has
Checks if map has the value for a key.
Signature:
func (cm *ConcurrentMap[K, V]) Has(key K) bool
Example:Run
package main
import (
"fmt"
"github.com/duke-git/lancet/v2/maputil"
)
func main() {
cm := maputil.NewConcurrentMap[string, int](100)
var wg1 sync.WaitGroup
wg1.Add(5)
for i := 0; i < 5; i++ {
go func(n int) {
cm.Set(fmt.Sprintf("%d", n), n)
wg1.Done()
}(i)
}
wg1.Wait()
var wg2 sync.WaitGroup
wg2.Add(5)
for j := 0; j < 5; j++ {
go func(n int) {
ok := cm.Has(fmt.Sprintf("%d", n))
fmt.Println(ok) // true
wg2.Done()
}(j)
}
wg2.Wait()
}
ConcurrentMap_Range
Calls iterator sequentially for each key and value present in each of the shards in the map. If iterator returns false, range stops the iteration.
Signature:
func (cm *ConcurrentMap[K, V]) Range(iterator func(key K, value V) bool)
Example:Run
package main
import (
"fmt"
"github.com/duke-git/lancet/v2/maputil"
)
func main() {
cm := maputil.NewConcurrentMap[string, int](100)
var wg1 sync.WaitGroup
wg1.Add(5)
for i := 0; i < 5; i++ {
go func(n int) {
cm.Set(fmt.Sprintf("%d", n), n)
wg1.Done()
}(i)
}
wg1.Wait()
cm.Range(func(key string, value int) bool {
fmt.Println(value)
return true
})
}