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Go Change Elements of a Slice

Last Updated : May 04, 2025

Go slices elements can be directly changed by using index positions without creating a new slice.

Changing Slice Elements Using Index

You can modify a specific element in a slice by assigning a new value to its index.

Example

package main
import "fmt"

func main() {
    names := []string{"Amit", "Bhavna", "Chetan"}

    names[1] = "Divya" // Changing the second element

    fmt.Println("Updated names slice:", names)
}

When executed, this program outputs:

Updated names slice: [Amit Divya Chetan]

Changing Elements in a Loop

You can use a for loop to iterate through a slice and update elements based on a condition or logic.

Example

package main
import "fmt"

func main() {
    numbers := []int{10, 20, 30}

    for i := 0; i < len(numbers); i++ {
        numbers[i] = numbers[i] * 2 // Doubling each element
    }

    fmt.Println("Doubled numbers:", numbers)
}

When executed, this program outputs:

Doubled numbers: [20 40 60]

Changing Elements Using range

When using range to iterate over a slice, you receive a copy of each value, so modifying it directly doesn't change the original slice. To update elements, use the index returned by range.

Example

package main
import "fmt"

func main() {
    scores := []int{55, 65, 75}

    for i, _ := range scores {
        scores[i] += 5 // Adding 5 to each score
    }

    fmt.Println("Updated scores:", scores)
}

When executed, this program outputs:

Updated scores: [60 70 80]

Exercise

Select the correct option to complete each statement about modifying elements of a slice in Go.

1. To change the value of an element at a specific index in a slice, use the syntax ___. --Select-- slice[i] = newValue slice.set(i, newValue) slice[i].update(newValue)
2. Modifying a slice element directly affects the ___ it is derived from. --Select-- underlying array copy of the slice garbage collector
3. To update multiple elements in a slice, you can use a ___. --Select-- for loop switch statement select case