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The Way to Go

Solution Review: Filtering with Higher-Order Functions

This lesson discusses the solution to the challenge given in the previous lesson.

We'll cover the following...
Go (1.6.2)
package main
import (
	"fmt"
)
func main() {
	s := []int{0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
	s = Filter(s, even)
	fmt.Println(s)
}
// Filter returns a new slice holding only
// the elements of s that satisfy fn()
func Filter(s []int, fn func(int) bool) []int {
	var p []int // == nil
	for _, i := range s {
		if fn(i) {
			p = append(p, i)
		}
	}
	return p
}
func even(n int) bool {
	if n%2 == 0 {
		return true
	}
	return false
}

The program above has one basic function. The function even takes n as a parameter and returns a boolean value (see its header on line 24). If n is even, it will return true. Otherwise, it will return false. See the header of the Filter function on line 14. It takes a slice of ...