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Unknwon
2015-02-23 02:49:28 -05:00
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eBook/08.5.md
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@@ -1,4 +1,7 @@
#8.5 map排序
# 8.5 map 的排序
192
map默认是无序的，不管是按照key还是按照value默认都不排序（参见8.3节）
如果你想为map排序，需要将key（或者value）拷贝到一个slice，再对slice排序（使用sort包，参见7.6.6），然后可以使用slice的for-range方法打印出所有的key和value。
@@ -6,21 +9,21 @@ map默认是无序的，不管是按照key还是按照value默认都不排序（
下面有一个示例：
示例 8.6 [sort_map.go](examples/chapter_8/sort_map.go)
// the telephone alphabet:
package main
import (
"fmt"
"sort"
)
var (
barVal = map[string]int{"alpha": 34, "bravo": 56, "charlie": 23,
"delta": 87, "echo": 56, "foxtrot": 12,
"golf": 34, "hotel": 16, "indio": 87,
"juliet": 65, "kili": 43, "lima": 98}
)
func main() {
fmt.Println("unsorted:")
for k, v := range barVal {
@@ -42,9 +45,9 @@ map默认是无序的，不管是按照key还是按照value默认都不排序（
输出结果：
unsorted:
Key: bravo, Value: 56 / Key: echo, Value: 56 / Key: indio, Value: 87 / Key: juliet, Value: 65 / Key: alpha, Value: 34 / Key: charlie, Value: 23 / Key: delta, Value: 87 / Key: foxtrot, Value: 12 / Key: golf, Value: 34 / Key: hotel, Value: 16 / Key: kili, Value: 43 / Key: lima, Value: 98 /
Key: bravo, Value: 56 / Key: echo, Value: 56 / Key: indio, Value: 87 / Key: juliet, Value: 65 / Key: alpha, Value: 34 / Key: charlie, Value: 23 / Key: delta, Value: 87 / Key: foxtrot, Value: 12 / Key: golf, Value: 34 / Key: hotel, Value: 16 / Key: kili, Value: 43 / Key: lima, Value: 98 /
sorted:
Key: alpha, Value: 34 / Key: bravo, Value: 56 / Key: charlie, Value: 23 / Key: delta, Value: 87 / Key: echo, Value: 56 / Key: foxtrot, Value: 12 / Key: golf, Value: 34 / Key: hotel, Value: 16 / Key: indio, Value: 87 / Key: juliet, Value: 65 / Key: kili, Value: 43 / Key: lima, Value: 98 / [fangjun@st01-dstream-0001.st01.baidu.com go]$ sz -be sort_map.go
Key: alpha, Value: 34 / Key: bravo, Value: 56 / Key: charlie, Value: 23 / Key: delta, Value: 87 / Key: echo, Value: 56 / Key: foxtrot, Value: 12 / Key: golf, Value: 34 / Key: hotel, Value: 16 / Key: indio, Value: 87 / Key: juliet, Value: 65 / Key: kili, Value: 43 / Key: lima, Value: 98 / [fangjun@st01-dstream-0001.st01.baidu.com go]$ sz -be sort_map.go
但是如果你想要一个排序的列表你最好使用结构体slice，这样会更有效：