英文:
Call a variadic function in Go
问题
我有一段代码，在其中调用了filepath.Join，如下所示的程序所描述。
然而，我遇到了一个错误。
程序：
package main
import (
"fmt"
"path/filepath"
)
func main() {
myVal := joinPath("dir1", "dir2")
fmt.Println(myVal)
}
func joinPath(dirs ...string) string {
return filepath.Join("mydir", dirs...)
}
错误：
./prog.go:16:32: 调用filepath.Join时参数过多 拥有 (string, []string) 期望 (...string)
虽然我知道这是一个合法的错误，但我该如何使用Join方法连接路径并设置默认的父目录呢？
英文:
I have code where I am calling filepath.Join as described in the following program.
However, I see an error
Program:
package main
import (
"fmt"
"path/filepath"
)
func main() {
myVal := joinPath("dir1", "dir2")
fmt.Println(myVal)
}
func joinPath(dirs ...string) string {
return filepath.Join("mydir", dirs...)
}
Error:
./prog.go:16:32: too many arguments in call to filepath.Join
have (string, []string)
want (...string)
While I know this is a legitimate error, how do I join the path with a default parent directory using Join
答案1
得分: 2
你不能在可变参数中混合使用切片和显式元素，详细信息请参考https://stackoverflow.com/questions/28625546/mixing-exploded-slices-and-regular-parameters-in-variadic-functions/28626170#28626170
然而，在你的特殊情况下，你可以调用filepath.Join()两次，得到相同的结果：
func joinPath(dirs ...string) string {
return filepath.Join("mydir", filepath.Join(dirs...))
}
你也可以准备一个包含所有元素的切片，并像这样传递：
func joinPath(dirs ...string) string {
return filepath.Join(append([]string{"mydir"}, dirs...)...)
}
两种方法都会返回并输出以下结果（可以在Go Playground上尝试）：
mydir/dir1/dir2
英文:
You can't mix a slice and explicit elements for a variadic parameter, for details, see https://stackoverflow.com/questions/28625546/mixing-exploded-slices-and-regular-parameters-in-variadic-functions/28626170#28626170
However, in your special case you may call filepath.Join() twice, and get the same result:
func joinPath(dirs ...string) string {
return filepath.Join("mydir", filepath.Join(dirs...))
}
You may also prepare a slice with all elements, and pass that like this:
func joinPath(dirs ...string) string {
return filepath.Join(append([]string{"mydir"}, dirs...)...)
}
Both will return and output (try them on the Go Playground):
mydir/dir1/dir2
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