如何检查interface {}是否是切片 [英] How to check if interface{} is a slice
问题描述
我是go的noob)所以我的问题可能是愚蠢的,但无法找到答案,所以。
我需要一个函数:
func name(v interface {}){
if_slice(){
for _,i:= range v {
my_var:= i。(MyInterface)
... do smth
}
} else {
my_var:= v。(MyInterface)
... do smth
}
}
我该怎么做 is_slice
在Go?感谢任何帮助。
type switch 是最简单和最方便的解决方案:
func name v接口{}){
switch x:= v。(type){
case [] MyInterface:
fmt.Println([] MyInterface,len:,len(x) )
for _,i:= range x {
fmt.Println(i)
}
case MyInterface:
fmt.Println(MyInterface:,x )
默认值:
fmt.Printf(不支持的类型:%T \ n,x)
}
}
x
变量已经是该类型的,所以你可以使用它。
测试它:
类型MyInterface接口{
io.Writer
}
var i MyInterface = os.Stdout
nam e(i)
var s = [] MyInterface {i,i}
名称
名称(别的东西)
输出(在 Go Playground ):
MyInterface:& {0x1040e110}
[] MyInterface,len:2
& {0x1040e110}
& {0x1040e110}
不支持的类型:字符串
对于单一类型的检查,您也可以使用键入断言:
if x,ok:= v。([] MyInterface); OK {
// x是[]的类型[] MyInterface
for _,i:=范围x {
fmt.Println(i)
}
} else {
// x不是类型[] MyInterface或它是零
}
还有其他一些方法,使用包 反映
你可以写一个更一般的(更慢的)解决方案,但是如果你刚开始使用Go,你就不应该深入思考。
I'm noob in Go :) so my question may be stupid, but can't find answer, so.
I need a function:
func name (v interface{}) {
if is_slice() {
for _, i := range v {
my_var := i.(MyInterface)
... do smth
}
} else {
my_var := v.(MyInterface)
... do smth
}
}
How can I do is_slice
in Go? Appreciate any help.
In your case the type switch is the simplest and most convenient solution:
func name(v interface{}) {
switch x := v.(type) {
case []MyInterface:
fmt.Println("[]MyInterface, len:", len(x))
for _, i := range x {
fmt.Println(i)
}
case MyInterface:
fmt.Println("MyInterface:", x)
default:
fmt.Printf("Unsupported type: %T\n", x)
}
}
The case
branches enumerate the possible types, and inside them the x
variable will already be of that type, so you can use it so.
Testing it:
type MyInterface interface {
io.Writer
}
var i MyInterface = os.Stdout
name(i)
var s = []MyInterface{i, i}
name(s)
name("something else")
Output (try it on the Go Playground):
MyInterface: &{0x1040e110}
[]MyInterface, len: 2
&{0x1040e110}
&{0x1040e110}
Unsupported type: string
For a single type check you may also use type assertion:
if x, ok := v.([]MyInterface); ok {
// x is of type []MyInterface
for _, i := range x {
fmt.Println(i)
}
} else {
// x is not of type []MyInterface or it is nil
}
There are also other ways, using package reflect
you can write a more general (and slower) solution, but if you're just starting Go, you shouldn't dig into reflection yet.
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