Making all array of strings of same index

[Mirage_Tech (Mirage)]

Hi, so i have 3 arrays one of them is empty or not same index as other 2 i want to append that one with empty strings until its of same index which is 2.

package main

import "fmt"

func main() {
	arr1 := []string{"apple", "banana", "cherry"}
	arr2 := []string{"dog", "cat", "hamster"}
	arr3 := []string{}
	for _, arr := range [][]string{arr1, arr2, arr3} {
		if len(arr) < 1 {
			//fmt.Print(arr)
			for i := len(arr); i <= 2; i++ {
				arr = append(arr, "")
			}
		}
	}
	fmt.Print(arr1, arr2, arr3)

}

When i run it the last array is still empty with index 0.

Go Playground - The Go Programming Language

[skillian (Sean Killian)]

I’ve added some comments to your code below to demonstrate the problem.

package main

import "fmt"

func main() {
	arr1 := []string{"apple", "banana", "cherry"}
	arr2 := []string{"dog", "cat", "hamster"}
	arr3 := []string{}
	for _, arr /* this is a copy of one of arr1, arr2, arr3 */ := range [][]string{arr1, arr2, arr3 /* these are the slices by value */} {
		if len(arr) < 1 {
			//fmt.Print(arr)
			for i := len(arr); i <= 2; i++ {
				// you're appending and updating the local variable, arr, but not
				// reassigning back to arr1, arr2, arr3, etc.
				arr = append(arr, "")
			}
		}
	}
	fmt.Print(arr1, arr2, arr3)

}

A solution could be to use pointers to the slices so that you’re updating the originals: Go Playground - The Go Programming Language

Or you could copy the values back out: Go Playground - The Go Programming Language

[telo_tade]

Hi guys,

Use the “for i := 0; i < len(array); i++” syntax. It is so good that most programming languages support it. The for range must be used only when needed.

@skillian both your solutions are close, but not exactly what I would do. Simply iterate using the index i, and append to arr[i]