gobyexample/examples/collection-functions/collection-functions.go
2012-10-09 21:02:12 -07:00

94 lines
1.9 KiB
Go

package main
import "strings"
import "fmt"
func Index(strs []string, s string) int {
for i, str := range strs {
if s == str {
return i
}
}
return -1
}
func Include(elems []string, val string) bool {
return Index(elems, val) >= 0
}
func Any(elems []string, f func(string) bool) bool {
for _, v := range elems {
if f(v) {
return true
}
}
return false
}
func All(elems []string, f func(string) bool) bool {
for _, v := range elems {
if !f(v) {
return false
}
}
return true
}
func Filter(vs []string, f func(string) bool) []string {
vsf := make([]string, 0)
for _, v := range elems {
if f(v) {
vsf = append(vsf, v)
}
}
return vsf
}
func Map(strs []string, f func(string) string) []string {
mapped := make([]string, len(strs))
for i, v := range strs {
mapped[i] = f(v)
}
return mapped
}
func main() {
var strs = []string{"peach", "apple", "pear", "plum"}
fmt.Println(Index(strs, "pear"))
fmt.Println(Index(strs, "grape"))
fmt.Println()
fmt.Println(Include(strs, "pear"))
fmt.Println(Include(strs, "grape"))
fmt.Println()
fmt.Println(Any(strs, func(v string) bool {
return strings.HasPrefix(v, "p")
}))
fmt.Println(Any(strs, func(v string) bool {
return strings.HasPrefix(v, "g")
}))
fmt.Println()
fmt.Println(All(strs, func(v string) bool {
return strings.Contains(v, "a")
}))
fmt.Println(All(strs, func(v string) bool {
return strings.Contains(v, "p")
}))
fmt.Println()
fmt.Println(Filter(strs, func(v string) bool {
return strings.Contains(v, "p")
}))
fmt.Println()
fmt.Println(Map(strs, func(s string) string {
return strings.ToUpper(s)
}))
fmt.Println()
}
// todo: note no generics