88 lines
1.9 KiB
Go
88 lines
1.9 KiB
Go
package main
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import (
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"fmt"
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"strings"
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)
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// in Go it’s common to provide collection functions if and when they are specifically needed for your program and data types
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// Index returns the first index of the target string t, or -1 if no match is found
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func Index(vs []string, t string) int {
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for i, v := range vs {
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if v == t {
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return i
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}
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}
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return -1
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}
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// Include returns true if the target string t is in the slice
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func Include(vs []string, t string) bool {
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return Index(vs, t) >= 0
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}
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// Any returns true if one of the strings in the slice satisfies the predicate f
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func Any(vs []string, f func(string) bool) bool {
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for _, v := range vs {
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if f(v) {
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return true
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}
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}
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return false
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}
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// All returns true if all of the strings in the slice satisfy the predicate f
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func All(vs []string, f func(string) bool) bool {
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for _, v := range vs {
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if !f(v) {
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return false
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}
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}
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return true
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}
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// Filter returns a new slice containing all strings in the slice that satisfy the predicate f
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func Filter(vs []string, f func(string) bool) []string {
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vsf := make([]string, 0)
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for _, v := range vs {
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if f(v) {
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vsf = append(vsf, v)
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}
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}
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return vsf
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}
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// Map returns a new slice containing the results of applying the function f to each string in the original slice
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func Map(vs []string, f func(string) string) []string {
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vsm := make([]string, len(vs))
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for i, v := range vs {
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vsm[i] = f(v)
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}
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return vsm
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}
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func main() {
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// try out various collection functions
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var strs = []string{"peach", "apple", "pear", "plum"}
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fmt.Println(Index(strs, "pear"))
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fmt.Println(Include(strs, "grape"))
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fmt.Println(Any(strs, func(v string) bool {
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return strings.HasPrefix(v, "p")
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}))
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fmt.Println(All(strs, func(v string) bool {
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return strings.HasPrefix(v, "p")
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}))
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fmt.Println(Filter(strs, func(v string) bool {
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return strings.Contains(v, "e")
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}))
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fmt.Println(Map(strs, strings.ToUpper))
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}
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