freeCodeCamp/curriculum/challenges/english/02-javascript-algorithms-and-data-structures/basic-javascript/manipulate-arrays-with-pop.english.md

id, title, challengeType

id	title	challengeType
56bbb991ad1ed5201cd392cc	Manipulate Arrays With pop()	1

Description

Another way to change the data in an array is with the .pop() function. .pop() is used to "pop" a value off of the end of an array. We can store this "popped off" value by assigning it to a variable. In other words, .pop() removes the last element from an array and returns that element. Any type of entry can be "popped" off of an array - numbers, strings, even nested arrays.

var threeArr = [1, 4, 6];
var oneDown = threeArr.pop();
console.log(oneDown); // Returns 6
console.log(threeArr); // Returns [1, 4]

Instructions

Use the .pop() function to remove the last item from myArray, assigning the "popped off" value to removedFromMyArray.

Tests

tests:
  - text: <code>myArray</code> should only contain <code>[["John", 23]]</code>.
    testString: assert((function(d){if(d[0][0] == 'John' && d[0][1] === 23 && d[1] == undefined){return true;}else{return false;}})(myArray), '<code>myArray</code> should only contain <code>[["John", 23]]</code>.');
  - text: Use <code>pop()</code> on <code>myArray</code>
    testString: assert(/removedFromMyArray\s*=\s*myArray\s*.\s*pop\s*(\s*)/.test(code), 'Use <code>pop()</code> on <code>myArray</code>');
  - text: <code>removedFromMyArray</code> should only contain <code>["cat", 2]</code>.
    testString: assert((function(d){if(d[0] == 'cat' && d[1] === 2 && d[2] == undefined){return true;}else{return false;}})(removedFromMyArray), '<code>removedFromMyArray</code> should only contain <code>["cat", 2]</code>.');

Challenge Seed

// Example
var ourArray = [1,2,3];
var removedFromOurArray = ourArray.pop();
// removedFromOurArray now equals 3, and ourArray now equals [1,2]

// Setup
var myArray = [["John", 23], ["cat", 2]];

// Only change code below this line.
var removedFromMyArray;

After Test

(function(y, z){return 'myArray = ' + JSON.stringify(y) + ' & removedFromMyArray = ' + JSON.stringify(z);})(myArray, removedFromMyArray);

Solution

var myArray = [["John", 23], ["cat", 2]];
var removedFromMyArray = myArray.pop();