Posted on Feb 1, 2020

Daily Challenge #178 - Create Phone Numbers

Setup

Implement a function that accepts an array of 10 integers. Have the function return those numbers as a String in the form of a phone number. Please use the following format for the phone number: (XXX) XXX-XXXX. Integers in the array will be no larger than 9.

Example

createPhoneNumber([1, 2, 3, 4, 5, 6, 7, 8, 9, 0]) // should return (123) 456-7890

Tests

createPhoneNumber([1, 2, 3, 4, 5, 6, 7, 8, 9, 0])
createPhoneNumber([1, 1, 1, 1, 1, 1, 1, 1, 1, 1])
createPhoneNumber([1, 2, 3, 4, 5, 6, 7, 8, 9, 0])

Good luck!

This challenge comes from xDranik on CodeWars. Thank you to CodeWars, who has licensed redistribution of this challenge under the 2-Clause BSD License!

Want to propose a challenge idea for a future post? Email yo+challenge@dev.to with your suggestions!

Top comments (9)

Jehiel Martinez • Feb 1 '20

function createPhoneNumber(arr) { if(arr.length < 10) { return 'Your phone number is not from this country' } arr.splice(0,0, '(') arr.splice(4,0, ')') arr.splice(5,0, ' ') arr.splice(9,0, '-') return arr.join(''); };

Craig McIlwrath • Feb 1 '20

Haskell

createPhoneNumber :: [Int] -> String createPhoneNumber ns = let a = concatMap show $ take 3 ns b = concatMap show $ take 3 $ drop 3 ns c = concatMap show $ take 4 $ drop 6 ns in '(' : a ++ ") " ++ b ++ "-" ++ c

Valts Liepiņš • Feb 1 '20

Ruby

def createPhoneNumber d "(#{d[0..2].join}) #{d[3..5].join}-#{d[6..9].join}" end

SavagePixie • Feb 1 '20

Elixir

I'm sure there's a much simpler way, though.

defmodule Phone do def get_number([ a, b, c, d, e, f, g, h, i, j ]) do "(#{a}#{b}#{c}) #{d}#{e}#{f}-#{g}#{h}#{i}#{j}" end end

Edvinas Pranka • Feb 1 '20

function createPhoneNumber(n) { return `({n[0]}{n[1]}{n[2]}) {n[3]}{n[4]}{n[5]}-{n[6]}{n[7]}{n[8]}{n[9]}`; }

Mathanagopal Sankarasubramanian • Feb 2 '20

JAVA

 public static String getNumbers(int[] arr, int start, int end){ String number = ""; for(int i=start;i<=end;i++){ if((""+arr[i]).length()>=2) { System.out.println("Let all the numbers be of single digit (Number at position "+i+")."); System.exit(1); } number = number+arr[i]; } return number; } public static String generateNumbers(int[] arr){ if(arr.length<0) System.out.println("Not valid"); else{ String phoneNumber = "("+getNumbers(arr,0,2)+")"+getNumbers(arr,3,5)+"-"+getNumbers(arr,6,arr.length-1); return phoneNumber; } return ""; } public static void main(String[] args) { int[] arr = {1, 1, 1, 1, 1, 1, 1, 1, 1, 1}; System.out.println(generateNumbers(arr)); }

Lamonte • Feb 2 '20 • Edited

Dart - I'm all about being explicit and ensuring the expected result is what I want rather than trying to be creative and smart.

String createPhoneNumber(List<int> numbers) { numbers = numbers.takeWhile((num) => num < 10).toList(); if(numbers.length < 10) return null; var result = StringBuffer("("); for(var idx = 0; idx < numbers.length; idx++) { result.write(numbers[idx]); switch(idx) { case 2: result.write(") "); break; case 5: result.write("-"); break; } } return result.toString(); }

Kyle Jones • Feb 4 '20

In Python:

def createPhoneNumber(numbers): numbers = [str(i) for i in numbers] return "({}) {}-{}".format(''.join(numbers[:3]), ''.join(numbers[3:6]), ''.join(numbers[6:10])) print(createPhoneNumber([1, 2, 3, 4, 5, 6, 7, 8, 9, 0])) print(createPhoneNumber([1, 1, 1, 1, 1, 1, 1, 1, 1, 1]))

Amin • Feb 1 '20

JavaScript

const createPhoneNumber = ([a, b, c, d, e, f, g, h, i, j]) => `(${a}${b}${c}) ${d}${e}${f}-${g}${h}${i}${j}`;