How to iterate over different types in loop in Go?

In Go, in order to iterate over an array/slice, you would write something like this:

for _, v := range arr {
    fmt.Println(v)
}

However, I want to iterate over array/slice which includes different types (int, float64, string, etc...). In Python, I can write it out as follows:

a, b, c = 1, "str", 3.14
for i in [a, b, c]:
    print(i)

How can I do such a work in Go? As far as I know, both array and slice are supposed to allow only same-type object, right? (say, []int allows only int type object.)

Thanks.

As Go is a statically typed language, that won't be as easy as in Python. You will have to resort to type assertions, reflection or similar means.

Take a look at this example:

package main

import (
    "fmt"
)

func main() {
    slice := make([]interface{}, 3)
    slice[0] = 1
    slice[1] = "hello"
    slice[2] = true

    for _, v := range slice {
	    switch v.(type) {
	    case string:
		    fmt.Println("We have a string")
	    case int:
		    fmt.Println("That's an integer!")
		    // You still need a type assertion, as v is of type interface{}
		    fmt.Printf("Its value is actually %d\n", v.(int))
	    default:
		    fmt.Println("It's some other type")
	    }
    }
}

Here we construct a slice with the type of an empty interface (any type implements it), do a type switch and handle the value based on the result of that.

Unfortunately, you'll need this (or a similar method) anywhere where you'll be dealing with arrays of unspecified type (empty interface). Moreover, you'll probably need a case for every possible type, unless you have a way to deal with any object you could get.

One way would be to make all of the types you want to store implement some interface of yours and then only use those objects through that interface. That's kind of how fmt handles generic arguments – it simply calls String() on any object to get its string representation.