Returns a new slice populated with the results of calling the provided function on every element in the collection.

Implement an appropriate function for each type conversion.
Use make() to create an appropriate slice.
Use range to iterate over elements in the given collection, setting the value at the same index in the resulting slice based on the result of fn.
The functions can be tweaked to allow for an index to be passed to fn as a second argument, if desired.

代码实现

func MapInt(arr []int, fn func(int) int) []int {
    arm := make([]int, len(arr))
    for i, v := range arr { arm[i] = fn(v) }
    return arm
}
func MapIntFloat64(arr []int, fn func(int) float64) []float64 {
    arm := make([]float64, len(arr))
    for i, v := range arr { arm[i] = fn(v) }
    return arm
}
func MapIntBool(arr []int, fn func(int) bool) []bool {
    arm := make([]bool, len(arr))
    for i, v := range arr { arm[i] = fn(v) }
    return arm
}
func MapIntString(arr []int, fn func(int) string) []string {
    arm := make([]string, len(arr))
    for i, v := range arr { arm[i] = fn(v) }
    return arm
}

func MapFloat64(arr []float64, fn func(float64) float64) []float64 {
    arm := make([]float64, len(arr))
    for i, v := range arr { arm[i] = fn(v) }
    return arm
}
func MapFloat64Int(arr []float64, fn func(float64) int) []int {
    arm := make([]int, len(arr))
    for i, v := range arr { arm[i] = fn(v) }
    return arm
}
func MapFloat64Bool(arr []float64, fn func(float64) bool) []bool {
    arm := make([]bool, len(arr))
    for i, v := range arr { arm[i] = fn(v) }
    return arm
}
func MapFloat64String(arr []float64, fn func(float64) string) []string {
    arm := make([]string, len(arr))
    for i, v := range arr { arm[i] = fn(v) }
    return arm
}

func MapBool(arr []bool, fn func(bool) bool) []bool {
    arm := make([]bool, len(arr))
    for i, v := range arr { arm[i] = fn(v) }
    return arm
}
func MapBoolInt(arr []bool, fn func(bool) int) []int {
    arm := make([]int, len(arr))
    for i, v := range arr { arm[i] = fn(v) }
    return arm
}
func MapBoolFloat64(arr []bool, fn func(bool) float64) []float64 {
    arm := make([]float64, len(arr))
    for i, v := range arr { arm[i] = fn(v) }
    return arm
}
func MapBoolString(arr []bool, fn func(bool) string) []string {
    arm := make([]string, len(arr))
    for i, v := range arr { arm[i] = fn(v) }
    return arm
}

func MapString(arr []string, fn func(string) string) []string {
    arm := make([]string, len(arr))
    for i, v := range arr { arm[i] = fn(v) }
    return arm
}
func MapStringInt(arr []string, fn func(string) int) []int {
    arm := make([]int, len(arr))
    for i, v := range arr { arm[i] = fn(v) }
    return arm
}
func MapStringFloat64(arr []string, fn func(string) float64) []float64 {
    arm := make([]float64, len(arr))
    for i, v := range arr { arm[i] = fn(v) }
    return arm
}
func MapStringBool(arr []string, fn func(string) bool) []bool {
    arm := make([]bool, len(arr))
    for i, v := range arr { arm[i] = fn(v) }
    return arm
}

使用样例

import "fmt"

ints := []int{1, 2, 3}
addTwo := func(x int) int { return x + 2 }
dollarString := func(x int) string { return fmt.Sprintf("$%d", x) }
MapInt(ints, addTwo) // [3 4 5]
MapIntString(ints, dollarString) // ["$1" "$2" "$3"]

floats := []float64{3.0, 2.0, 0.0}
gtTwo := func(x float64) bool { return x > 2.0 }
MapFloat64Bool(floats, gtTwo) // [true false false]

strings := []string{"go", "is", "cool"}
strLen := func(x string) int { return len(x) }
MapStringInt(strings, strLen) // [2 2 4]