Slices (Arrays)

In this lesson you will learn the basics of slices (variable-length arrays) in Go so you can handle several pieces of data together. This is for anyone searching for "Go slices how to use".

An array is like a shelf of numbered drawers. In Go a variable-length array is called a slice. range takes the items out one at a time.

The sample code builds a slice with fruits := []string{"apple", "orange", "grape"} and prints each item with its number, taking the index and the element together with for i, fruit := range fruits. Go provides slices, whose elements can be freely added and removed, alongside fixed-length arrays.

A common stumbling block for beginners is that a slice holds a reference to an underlying array. Assigning a slice to another variable shares the same data, so changing one can affect the other - the copying behaviour sometimes needs care.

In real-world development slices are used almost everywhere in preference to fixed-length arrays, making them the basic data structure you will meet constantly in Go code.

📖 Reference code

package main

import "fmt"

func main() {
    fruits := []string{"apple", "orange", "grape"}
    for i, fruit := range fruits {
        fmt.Printf("%d: %s\n", i+1, fruit)
    }
}

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🧪 This site can't compile or run Go directly, so it checks on the spot whether what you typed matches the reference code (scoring happens entirely in your browser — nothing is sent anywhere).