golang type conversion

map[string]interface{} is not the same as map[string]string. Type interface{} is not the same as type string.

If they are both map[string]string:

package main

import "fmt"

func main() {
    v := map[string]string{"hello": "world"}
    checkCast(v)

}

func checkCast(v interface{}) {
    _, isCorrectType := v.(map[string]string)
    if !isCorrectType {
        fmt.Printf("incorrect type")
        return
    }
}

Output:

[no output]

---

The statement v.(map[string]string) is a type assertion, not a cast.

The Go Programming Language Specification

Type assertions

For an expression x of interface type and a type T, the primary expression

x.(T)

asserts that x is not nil and that the value stored in x is of type T. The notation x.(T) is called a type assertion.

---

Go has conversions.

The Go Programming Language Specification

Conversions

Conversions are expressions of the form T(x) where T is a type and x is an expression that can be converted to type T.

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edited Jul 4 '14 at 20:01

 

 

answered Jul 4 '14 at 19:45

peterSO

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•  
  is there a way to cast in Go? – Karan Jul 4 '14 at 19:56
• 1
  @Karan: See my revised answer. Go has conversions. – peterSO Jul 4 '14 at 20:05