Go map of functions | 易学教程

问题

I have Go program that has a function defined. I also have a map that should have a key for each function. How can I do that?

I have tried this, but this doesn't work.

func a(param string) {

}

m := map[string] func {
    'a_func': a,
}

for key, value := range m {
   if key == 'a_func' {
    value(param) 
   }
}

回答1:

Are you trying to do something like this? I've revised the example to use varying types and numbers of function parameters.

package main

import "fmt"

func f(p string) {
    fmt.Println("function f parameter:", p)
}

func g(p string, q int) {
    fmt.Println("function g parameters:", p, q)
}

func main() {
    m := map[string]interface{}{
        "f": f,
        "g": g,
    }
    for k, v := range m {
        switch k {
        case "f":
            v.(func(string))("astring")
        case "g":
            v.(func(string, int))("astring", 42)
        }
    }
}

回答2:

m := map[string]func(string, string)

Works if you know the signature (and all the funcs have the same signature) I think this is cleaner/safer than using interface{}

回答3:

You can define a type if functions are same interface.

package main

import "log"

type fn func (string)

func foo(msg string) {
  log.Printf("foo! Message is %s", msg)
}

func bar(msg string) {
  log.Printf("bar! Message is %s", msg)
}

func main() {
  m := map[string] fn {
    "f": foo,
    "b": bar,
  }
  log.Printf("map is %v", m)
  m["f"]("Hello")
  m["b"]("World")
}

回答4:

@Seth Hoenig's answer helped me best, but I just wanted to add that Go accepts functions with defined return value as well:

package main

func main() {
    m := map[string]func(string) string{
        "foo": func(s string) string { return s + "nurf" },
    }

    m["foo"]("baz") // "baznurf"
}

If you think it's ugly, you could always use a type (see @smagch's answer).

来源：https://stackoverflow.com/questions/6769020/go-map-of-functions

标签

map

key-value

func