Check if all array lengths match in Go

October 19, 2022

I have a function which checks if array lengths are the same:

func checkArrayLengthsMatch(desiredLength int, arrays ...[]any) bool {
    for _, array := range arrays {
        if len(array) != desiredLength {
            return false
        }
    }
    return true
}

But this doesn’t work because of the []any.

array1 := []string{"1", "2"}
array2 := []int{1, 2}
checkArrayLengthsMatch(2, array1, array2)

gives the error cannot use array1 (variable of type []string) as type []any in argument to checkArrayLengthsMatch

Is there any way to achieve this functionality without having to write a long if statement? (e.g. if len(array1) != 2 || len(array2) != 2) Generics?

I want to be able to support checking arrays of various types.

Go playground link: https://go.dev/play/p/yKisBIOZktI

>Solution :

If you need to pass different types of arrays to the same function, generics won’t work, but reflection will:

func checkArrayLengthsMatch(desiredLength int, arrays ...any) bool {
    for _, array := range arrays {
        if reflect.ValueOf(array).Len() != desiredLength {
            return false
        }
    }
    return true
}

This will also work for maps, channels, and strings.