# Concatenate an array with itself – HackerRank Solution

In this post, we will solve Concatenate an array with itself HackerRank Solution. This problem (Concatenate an array with itself) is a part of Linux Shell series.

Contents

Given a list of countries, each on a new line, your task is to read them into an array. Then, concatenate the array with itself (twice) – so that you have a total of three repetitions of the original array – and then display the entire concatenated array, with aÂ spaceÂ between each of the countries’ names.

## Input Format

A list of country names. The only characters present in the country names will be upper or lower case characters and hyphens.

## Output Format

Display the entire concatenated array, with aÂ spaceÂ between each of them.

Sample Input

``````Namibia
Nauru
Nepal
Netherlands
NewZealand
Nicaragua
Niger
Nigeria
NorthKorea
Norway``````

Sample Output

``Namibia Nauru Nepal Netherlands NewZealand Nicaragua Niger Nigeria NorthKorea Norway Namibia Nauru Nepal Netherlands NewZealand Nicaragua Niger Nigeria NorthKorea Norway Namibia Nauru Nepal Netherlands NewZealand Nicaragua Niger Nigeria NorthKorea Norway``

Explanation

The entire concatenated array has been displayed.

## Solution – Concatenate an array with itself – HackerRank Solution

```#Given a list of countries, each on a new line, your task is to read them into an array. Then, concatenate the array with itself (twice) - so that you have a total of three repetitions of the original array - and then display the entire concatenated array, with a space between each of the countries' names
arr=(\$(cat))
arr=("\${arr[@]}" "\${arr[@]}" "\${arr[@]}")
echo \${arr[@]}
```

Note: This problem (Concatenate an array with itself) is generated by HackerRank but the solution is provided by CodingBroz. This tutorial is only for Educational and Learning purpose.