英文:
Convert chan to non chan in golang
问题
是否可以让函数funcWithNonChanResult具有以下接口：
func funcWithNonChanResult() int {
如果我想要它使用具有以下接口的函数funcWithChanResult：
func funcWithChanResult() chan int {
换句话说，我是否可以将chan int转换为int？或者我必须在所有使用funcWithChanResult的函数中使用chan int作为返回类型？
目前，我尝试了以下方法：
result = funcWithChanResult()
// 无法将类型为chan int的funcWithChanResult()分配给类型为int的result
result <- funcWithChanResult()
// 对非通道类型int进行发送操作：result <- funcWithChanResult()
完整代码：
```go
package main
import (
"fmt"
"time"
)
func getIntSlowly() int {
time.Sleep(time.Millisecond * 500)
return 123
}
func funcWithChanResult() chan int {
chanint := make(chan int)
go func() {
chanint <- getIntSlowly()
}()
return chanint
}
func funcWithNonChanResult() int {
var result int
result = funcWithChanResult()
// result <- funcWithChanResult()
return result
}
func main() {
fmt.Println("Received first int:", <-funcWithChanResult())
fmt.Println("Received second int:", funcWithNonChanResult())
}
英文:
Is it possible to let function funcWithNonChanResult have the following interface:
func funcWithNonChanResult() int {
And if I want it to use function funcWithChanResult with the interface:
func funcWithChanResult() chan int {
In other words, can I somehow convert chan int to int? Or I must have chan int result type in all the functions which use funcWithChanResult?
Currently, I tried these methods:
result = funcWithChanResult()
// cannot use funcWithChanResult() (type chan int) as type int in assignment
result <- funcWithChanResult()
// invalid operation: result <- funcWithChanResult() (send to non-chan type int)
Full code:
package main
import (
"fmt"
"time"
)
func getIntSlowly() int {
time.Sleep(time.Millisecond * 500)
return 123
}
func funcWithChanResult() chan int {
chanint := make(chan int)
go func() {
chanint <- getIntSlowly()
}()
return chanint
}
func funcWithNonChanResult() int {
var result int
result = funcWithChanResult()
// result <- funcWithChanResult()
return result
}
func main() {
fmt.Println("Received first int:", <-funcWithChanResult())
fmt.Println("Received second int:", funcWithNonChanResult())
}
答案1
得分: 9
一个chan int是一个包含int值的通道，它不是一个单独的int值，而是一个int值的来源（或者也可以是一个目标，在你的情况下你将其用作来源）。
因此，你不能将chan int转换为int。你可以做的，也可能是你的意思是使用从chan int接收到的值（类型为int）作为int值。
这不是一个问题：
var result int
ch := funcWithChanResult()
result = <- ch
或者更简洁一些：
result := <- funcWithChanResult()
将其与return语句结合使用：
func funcWithNonChanResult() int {
return <-funcWithChanResult()
}
输出（如预期）：
接收到的第一个int值：123
接收到的第二个int值：123
在Go Playground上尝试你修改后的可工作示例。
英文:
A chan int is a channel of int values, it is not a single int value but a source of int values (or also a target, but in your case you use it as source).
So therefore you can't convert chan int to int. What you can do and probably what you mean is use a value (of type int) received from a chan int as an int value.
This is not a problem:
var result int
ch := funcWithChanResult()
result = <- ch
Or more compact:
result := <- funcWithChanResult()
Combine this with the return statement:
func funcWithNonChanResult() int {
return <-funcWithChanResult()
}
Output (as expected):
Received first int: 123
Received second int: 123
Try your modified, working example on the Go Playground.
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