How to Concatenate Two Slices in Go

Using golang’s append() function we can concatenate two slices in Go.

Let’s go through an example to understand it further.

I have created two integer slices and appending sliceOne to the another slice sliceTwo.

package main

import (
	"fmt"
)

func main() {
	sliceOne := []int{1, 2}
	sliceTwo := []int{3, 4}

	result := append(sliceOne, sliceTwo)
	fmt.Printf("c: %v\n", result)

}

If you run above code you will get following error.

cannot use sliceTwo (type []int) as type int in append

append() is a variadic function, that means we can pass multiple arguments to it.

//func append(slice []Type, elems ...Type) []Type

append([]int{1, 2},3)    //1,2,3 
append([]int{1, 2},3,4)  //1,2,3,4

But in the above example, we trying to append slice of integers instead of single integer.

That’s why we are getting type mismatch error.

To pass slice as a parameter to append() method use ....

package main

import (
	"fmt"
)

func main() {
	sliceOne := []int{1, 2}
	sliceTwo := []int{3, 4}

	result := append(sliceOne, sliceTwo...)
	fmt.Printf("c: %v\n", result)

}

OUTPUT is

c: [1 2 3 4]

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Arunkumar Gudelli

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