golang slice分割和append copy還是引用
Posted on 2013-11-20 18:46 oathleo 閱讀(6672) 評(píng)論(1) 編輯 收藏 所屬分類: Golang1.slice1:= slice[0:2]
引用,非復(fù)制,所以任何對(duì)slice1或slice的修改都會(huì)影響對(duì)方
data := []int{1, 2, 3, 4, 5, 6, 7, 8, 9, 0}
data1 := data[0:2]
data1[0] = 99
fmt.Println(data1)
fmt.Println(data)
[99 2]
[99 2 3 4 5 6 7 8 9 0]
2.append
append 比較特殊
聲明:
源slice= src
添加slice = app
結(jié)果slice=tar
1)如果len(src) + len(app) <= cap(src) src和tar 是指向同一數(shù)據(jù)引用 ,即修改src或tar,會(huì)影響對(duì)方
2)否則 tar 是copy的方式 src + app ,即修改src或tar,不會(huì)影響對(duì)方
無(wú)論哪種情況不會(huì)影響app,因?yàn)閍pp都會(huì)用copy的方式進(jìn)入tar
func test2() {
data := make([]int, 10, 20)
data[0] = 1
data[1] = 2
dataappend := make([]int, 10, 20)//len <=10 則 result[0] = 99 會(huì) 影響源Slice
dataappend[0] = 1
dataappend[1] = 2
result := append(data, dataappend...)
result[0] = 99
result[11] = 98
fmt.Println("length:", len(data), ":", data)
fmt.Println("length:", len(result), ":", result)
fmt.Println("length:", len(dataappend), ":", dataappend)
}