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xmap

import "github.com/dashjay/xiter/pkg/xmap"

Index

func Clone

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

func CoalesceMaps

func CoalesceMaps[M ~map[K]V, K comparable, V any](maps ...M) M

CoalesceMaps combines multiple maps into a single map. When duplicate keys are encountered, the value from the rightmost (last) map in the input slice takes precedence. It iterates through the input maps, converts them to sequences of key-value pairs, concatenates these sequences, and then converts the combined sequence back into a new map.

Parameters:

maps ...M: A variadic slice of maps of type M. Each map must have comparable keys K and values V.

Returns:

M: A new map containing all key-value pairs from the input maps, with later maps overriding
   values for duplicate keys.

Example:

map1 := map[string]int{"a": 1, "b": 2}
map2 := map[string]int{"b": 3, "c": 4}
map3 := map[string]int{"d": 5}

// CoalesceMaps will combine map1, map2, and map3.
// For key "b", the value 3 from map2 will override 2 from map1.
result := CoalesceMaps(map1, map2, map3)
// result will be map[string]int{"a": 1, "b": 3, "c": 4, "d": 5}

func Copy

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

func Delete

func Delete[K comparable, V any](m map[K]V, k K) (old V, deleted bool)

Delete removes a key from the map and returns the old value and whether it was deleted. If the key exists, it removes the key-value pair and returns the old value with deleted=true. If the key doesn't exist, it returns the zero value with deleted=false.

EXAMPLE:

m := map[string]int{"a": 1, "b": 2}
old, deleted := xmap.Delete(m, "b")
// old=2, deleted=true, m is now {"a": 1}
old, deleted = xmap.Delete(m, "c")
// old=0, deleted=false, m remains {"a": 1}

func DeleteIf

func DeleteIf[K comparable, V any](m map[K]V, k K, c func(K, V) bool) (old V, deleted bool)

DeleteIf removes a key from the map only if the condition function returns true. It returns the old value and whether it was deleted. If the key exists and the condition is true, it removes the key-value pair and returns the old value with deleted=true. Otherwise, it returns the zero value with deleted=false.

EXAMPLE:

m := map[string]int{"a": 1, "b": 2}
old, deleted := xmap.DeleteIf(m, "b", func(k string, v int) bool { return v > 1 })
// old=2, deleted=true, m is now {"a": 1}
old, deleted = xmap.DeleteIf(m, "b", func(k string, v int) bool { return v > 10 })
// old=0, deleted=false, m remains {"a": 1}
old, deleted = xmap.DeleteIf(m, "c", func(k string, v int) bool { return v > 0 })
// old=0, deleted=false (key doesn't exist), m remains {"a": 1}

func Equal

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

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

func Filter

func Filter[M ~map[K]V, K comparable, V any](in M, fn func(K, V) bool) M

Filter filters the map by the given function. Example:

m := map[string]int{"a": 1, "b": 2, "c": 3}
fn := func(k string, v int) bool {
	return v > 1
}
result := Filter(m, fn)
// result will be map[string]int{"b": 2, "c": 3}

func Find

func Find[K comparable, V any](in map[K]V, fn func(K, V) bool) (K, V, bool)

Find searches for the first key-value pair in the map that satisfies the given condition function. It returns the key, value, and whether such a pair was found. The search order is not guaranteed to be consistent due to the nature of Go's map iteration. If no pair satisfies the condition, it returns the zero key, zero value, and false.

EXAMPLE:

m := map[string]int{"a": 1, "b": 2, "c": 3}
key, value, found := xmap.Find(m, func(k string, v int) bool { return v > 1 })
// key could be "b" or "c", value=2 or 3, found=true (first match found)
key, value, found = xmap.Find(m, func(k string, v int) bool { return v > 10 })
// key="", value=0, found=false

func FindKey

func FindKey[K comparable, V any](in map[K]V, target K) (K, V, bool)

FindKey finds a key in the map and returns the key, its value, and whether it was found. This is essentially a wrapper around the built-in map lookup that returns the key along with the value. If the key exists, it returns the key, its value, and true. If the key doesn't exist, it returns the zero key, zero value, and false.

EXAMPLE:

m := map[string]int{"a": 1, "b": 2}
key, value, found := xmap.FindKey(m, "b")
// key="b", value=2, found=true
key, value, found = xmap.FindKey(m, "c")
// key="", value=0, found=false

func FindKeyO

func FindKeyO[K comparable, V any](in map[K]V, target K) optional.O[union.U2[K, V]]

FindKeyO finds a key in the map and returns the key-value pair as an optional.O[union.U2[K, V]]. If the key exists, it returns an optional containing a union.U2 with the key in T1 and value in T2. If the key doesn't exist, it returns an empty optional.

EXAMPLE:

m := map[string]int{"a": 1, "b": 2}
result := xmap.FindKeyO(m, "b")
// result.Ok() == true, result.Must() contains union.U2[string, int]{T1: "b", T2: 2}
key := result.Must().T1 // "b"
value := result.Must().T2 // 2
result2 := xmap.FindKeyO(m, "c")
// result2.Ok() == false

func FindO

func FindO[K comparable, V any](in map[K]V, fn func(K, V) bool) optional.O[union.U2[K, V]]

FindO searches for the first key-value pair in the map that satisfies the given condition function. It returns the key-value pair as an optional.O[union.U2[K, V]]. The search order is not guaranteed to be consistent due to the nature of Go's map iteration. If a pair satisfies the condition, it returns an optional containing a union.U2 with the key in T1 and value in T2. If no pair satisfies the condition, it returns an empty optional.

EXAMPLE:

m := map[string]int{"a": 1, "b": 2, "c": 3}
result := xmap.FindO(m, func(k string, v int) bool { return v > 1 })
// result.Ok() == true, result.Must() contains union.U2[string, int] with key and value of first match
key := result.Must().T1 // could be "b" or "c"
value := result.Must().T2 // could be 2 or 3
result2 := xmap.FindO(m, func(k string, v int) bool { return v > 10 })
// result2.Ok() == false

func Keys

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

func MapKeys

func MapKeys[K comparable, V1 any](in map[K]V1, fn func(K, V1) K) map[K]V1

MapKeys transforms the keys of a map using the provided function while keeping values unchanged. This is useful for transforming data structures while preserving the value associations.

Parameters:

in map[K]V1: The input map to transform
fn func(K, V1) K: A function that takes a key and its corresponding value, and returns a new key

Returns:

map[K]V1: A new map with the same values as the input map but with transformed keys

Example:

m := map[string]int{"a": 1, "b": 2, "c": 3}
fn := func(k string, v int) string {
	return k + "_key"
}
result := MapKeys(m, fn)
// result will be map[string]int{"a_key": 1, "b_key": 2, "c_key": 3}

func MapValues

func MapValues[K comparable, V1, V2 any](in map[K]V1, fn func(K, V1) V2) map[K]V2

MapValues transforms the values of a map using the provided function while keeping keys unchanged. This is useful for transforming data structures while preserving the key associations.

Parameters:

in M: The input map to transform
fn func(K, V1) V2: A function that takes a key and its corresponding value, and returns a new value

Returns:

map[K]V2: A new map with the same keys as the input map but with transformed values

Example:

m := map[string]int{"a": 1, "b": 2, "c": 3}
fn := func(k string, v int) string {
	return fmt.Sprintf("value_%d", v)
}
result := MapValues(m, fn)
// result will be map[string]string{"a": "value_1", "b": "value_2", "c": "value_3"}

func MaxKey

func MaxKey[K constraints.Ordered, V any](m map[K]V) optional.O[union.U2[K, V]]

MaxKey returns the maximum key in the map and its associated value as an optional.O[union.U2[K, V]]. If the map is empty, it returns an optional.O[union.U2[K, V]] with Ok() == false. The returned union.U2 contains the key in T1 and the value in T2.

EXAMPLE:

m := map[string]int{"b": 2, "a": 1, "c": 3}
result := xmap.MaxKey(m)
// result contains union.U2[string, int]{T1: "c", T2: 3}
maxKey := result.Must().T1 // "c"
maxValue := result.Must().T2 // 3
result2 := xmap.MaxKey(map[string]int{})
// result2.Ok() == false

func MaxValue

func MaxValue[K comparable, V constraints.Ordered](m map[K]V) optional.O[union.U2[K, V]]

MaxValue returns the maximum value in the map and its associated key as an optional.O[union.U2[K, V]]. If the map is empty, it returns an optional.O[union.U2[K, V]] with Ok() == false. The returned union.U2 contains the key in T1 and the maximum value in T2.

EXAMPLE:

m := map[string]int{"a": 1, "b": 3, "c": 2}
result := xmap.MaxValue(m)
// result contains union.U2[string, int]{T1: "b", T2: 3}
maxKey := result.Must().T1 // "b"
maxValue := result.Must().T2 // 3
result2 := xmap.MaxValue(map[string]int{})
// result2.Ok() == false

func MinKey

func MinKey[K constraints.Ordered, V any](m map[K]V) optional.O[union.U2[K, V]]

MinKey returns the minimum key in the map and its associated value as an optional.O[union.U2[K, V]]. If the map is empty, it returns an optional.O[union.U2[K, V]] with Ok() == false. The returned union.U2 contains the key in T1 and the value in T2.

EXAMPLE:

m := map[string]int{"b": 2, "a": 1, "c": 3}
result := xmap.MinKey(m)
// result contains union.U2[string, int]{T1: "a", T2: 1}
minKey := result.Must().T1 // "a"
minValue := result.Must().T2 // 1
result2 := xmap.MinKey(map[string]int{})
// result2.Ok() == false

func MinValue

func MinValue[K comparable, V constraints.Ordered](m map[K]V) optional.O[union.U2[K, V]]

MinValue returns the minimum value in the map and its associated key as an optional.O[union.U2[K, V]]. If the map is empty, it returns an optional.O[union.U2[K, V]] with Ok() == false. The returned union.U2 contains the key in T1 and the minimum value in T2.

EXAMPLE:

m := map[string]int{"a": 3, "b": 1, "c": 2}
result := xmap.MinValue(m)
// result contains union.U2[string, int]{T1: "b", T2: 1}
minKey := result.Must().T1 // "b"
minValue := result.Must().T2 // 1
result2 := xmap.MinValue(map[string]int{})
// result2.Ok() == false

func ToUnionSlice

func ToUnionSlice[M ~map[K]V, K comparable, V any](m M) []union.U2[K, V]

func ToXSyncMap

func ToXSyncMap[K comparable, V any](in map[K]V) *xsync.SyncMap[K, V]

ToXSyncMap converts a map to a xsync.SyncMap.

Parameters:

in map[K]V: The input map to convert

Returns:

*xsync.SyncMap[K, V]: A new xsync.SyncMap containing the same key-value pairs as the input map

func Update

func Update[K comparable, V any](m map[K]V, k K, v V) (old V, replaced bool)

Update updates the value for a key in the map and returns the old value and whether it was replaced. If the key exists, it updates the value and returns the old value with replaced=true. If the key doesn't exist, it adds the key-value pair and returns the zero value with replaced=false.

EXAMPLE:

m := map[string]int{"a": 1, "b": 2}
old, replaced := xmap.Update(m, "b", 20)
// old=2, replaced=true, m is now {"a": 1, "b": 20}
old, replaced = xmap.Update(m, "c", 3)
// old=0, replaced=false, m is now {"a": 1, "b": 20, "c": 3}

func UpdateIf

func UpdateIf[K comparable, V any](m map[K]V, k K, v V, c func(K, V) bool) (old V, replaced bool)

UpdateIf updates the value for a key in the map only if the condition function returns true. It returns the old value and whether it was replaced. If the key exists and the condition is true, it updates the value and returns the old value with replaced=true. Otherwise, it returns the zero value with replaced=false.

EXAMPLE:

m := map[string]int{"a": 1, "b": 2}
old, replaced := xmap.UpdateIf(m, "b", 20, func(k string, v int) bool { return v > 1 })
// old=2, replaced=true, m is now {"a": 1, "b": 20}
old, replaced = xmap.UpdateIf(m, "b", 200, func(k string, v int) bool { return v > 50 })
// old=0, replaced=false, m remains {"a": 1, "b": 20}
old, replaced = xmap.UpdateIf(m, "c", 3, func(k string, v int) bool { return v > 0 })
// old=0, replaced=false (key doesn't exist), m remains {"a": 1, "b": 20}

func Values

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

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