Shorter Way to Transform List Elements in Go

In Python, applying a function to each element in a list can be achieved using list comprehensions. However, in Go, a more verbose approach involving a loop is commonly used. This question explores a concise way to accomplish this operation in Go.

Python Solution:

list = [1,2,3]
str = ', '.join(multiply(x, 2) for x in list)

Go Solution (Original):

list := []int{1,2,3}
list2 := []int

for _,x := range list {
    list2 := append(list2, multiply(x, 2))
}

str := strings.Join(list2, ", ")

Shorter Go Solution (Go 1.18 ):

func Map[T, V any](ts []T, fn func(T) V) []V {
    result := make([]V, len(ts))
    for i, t := range ts {
        result[i] = fn(t)
    }
    return result
}

Usage:

input := []int{4, 5, 3}
outputInts := Map(input, func(item int) int { return item   1 })
outputStrings := Map(input, func(item int) string { return fmt.Sprintf("Item:%d", item) })

This Map function offers a concise and generic way to apply a function to a list of any type, resulting in a new list of transformed values.