mirror of
https://github.com/gopl-zh/gopl-zh.github.com.git
synced 2024-11-19 21:03:43 +00:00
48 lines
924 B
Go
48 lines
924 B
Go
// Copyright © 2016 Alan A. A. Donovan & Brian W. Kernighan.
|
|
// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
|
|
|
|
// See page 91.
|
|
|
|
//!+nonempty
|
|
|
|
// Nonempty is an example of an in-place slice algorithm.
|
|
package main
|
|
|
|
import "fmt"
|
|
|
|
// nonempty returns a slice holding only the non-empty strings.
|
|
// The underlying array is modified during the call.
|
|
func nonempty(strings []string) []string {
|
|
i := 0
|
|
for _, s := range strings {
|
|
if s != "" {
|
|
strings[i] = s
|
|
i++
|
|
}
|
|
}
|
|
return strings[:i]
|
|
}
|
|
|
|
//!-nonempty
|
|
|
|
func main() {
|
|
//!+main
|
|
data := []string{"one", "", "three"}
|
|
fmt.Printf("%q\n", nonempty(data)) // `["one" "three"]`
|
|
fmt.Printf("%q\n", data) // `["one" "three" "three"]`
|
|
//!-main
|
|
}
|
|
|
|
//!+alt
|
|
func nonempty2(strings []string) []string {
|
|
out := strings[:0] // zero-length slice of original
|
|
for _, s := range strings {
|
|
if s != "" {
|
|
out = append(out, s)
|
|
}
|
|
}
|
|
return out
|
|
}
|
|
|
|
//!-alt
|