Go集合函數實例

collection-functions.go的完整代碼如下所示 -

package main

import "strings"
import "fmt"

// Returns the first index of the target string t, or
// -1 if no match is found.
func Index(vs []string, t string) int {
for i, v := range vs {
if v == t {
return i
}
}
return -1
}

// Returns true if the target string t is in the
// slice.
func Include(vs []string, t string) bool {
return Index(vs, t) >= 0
}

// Returns true if one of the strings in the slice
// satisfies the predicate f.
func Any(vs []string, f func(string) bool) bool {
for _, v := range vs {
if f(v) {
return true
}
}
return false
}

// Returns true if all of the strings in the slice
// satisfy the predicate f.
func All(vs []string, f func(string) bool) bool {
for _, v := range vs {
if !f(v) {
return false
}
}
return true
}

// Returns a new slice containing all strings in the
// slice that satisfy the predicate f.
func Filter(vs []string, f func(string) bool) []string {
vsf := make([]string, 0)
for _, v := range vs {
if f(v) {
vsf = append(vsf, v)
}
}
return vsf
}

// Returns a new slice containing the results of applying
// the function f to each string in the original slice.
func Map(vs []string, f func(string) string) []string {
vsm := make([]string, len(vs))
for i, v := range vs {
vsm[i] = f(v)
}
return vsm
}

func main() {

// Here we try out our various collection functions.
var strs = []string{"peach", "apple", "pear", "plum"}

fmt.Println(Index(strs, "pear"))

fmt.Println(Include(strs, "grape"))

fmt.Println(Any(strs, func(v string) bool {
return strings.HasPrefix(v, "p")
}))

fmt.Println(All(strs, func(v string) bool {
return strings.HasPrefix(v, "p")
}))

fmt.Println(Filter(strs, func(v string) bool {
return strings.Contains(v, "e")
}))

// The above examples all used anonymous functions,
// but you can also use named functions of the correct
// type.
fmt.Println(Map(strs, strings.ToUpper))

}

F:\worksp\golang>go run collection-functions.go
2
false
true
false
[peach apple pear]
[PEACH APPLE PEAR PLUM]