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access-array-data-with-indexes.english.md
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accessing-nested-arrays.english.md
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appending-variables-to-strings.english.md
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chaining-if-else-statements.english.md
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comparison-with-the-inequality-operator.english.md
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comparison-with-the-strict-equality-operator.english.md
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comparisons-with-the-logical-and-operator.english.md
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compound-assignment-with-augmented-addition.english.md
compound-assignment-with-augmented-division.english.md
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concatenating-strings-with-plus-operator.english.md
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constructing-strings-with-variables.english.md
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delete-properties-from-a-javascript-object.english.md
divide-one-decimal-by-another-with-javascript.english.md
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escape-sequences-in-strings.english.md
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generate-random-fractions-with-javascript.english.md
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global-scope-and-functions.english.md
global-vs.-local-scope-in-functions.english.md
golf-code.english.md
increment-a-number-with-javascript.english.md
initializing-variables-with-the-assignment-operator.english.md
introducing-else-if-statements.english.md
introducing-else-statements.english.md
iterate-odd-numbers-with-a-for-loop.english.md
iterate-through-an-array-with-a-for-loop.english.md
iterate-with-javascript-do...while-loops.english.md
iterate-with-javascript-for-loops.english.md
iterate-with-javascript-while-loops.english.md
local-scope-and-functions.english.md
logical-order-in-if-else-statements.english.md
manipulate-arrays-with-pop.english.md
manipulate-arrays-with-push.english.md
manipulate-arrays-with-shift.english.md
manipulate-arrays-with-unshift.english.md
manipulating-complex-objects.english.md
modify-array-data-with-indexes.english.md
multiple-identical-options-in-switch-statements.english.md
multiply-two-decimals-with-javascript.english.md
multiply-two-numbers-with-javascript.english.md
nest-one-array-within-another-array.english.md
nesting-for-loops.english.md
passing-values-to-functions-with-arguments.english.md
practice-comparing-different-values.english.md
profile-lookup.english.md
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record-collection.english.md
replace-loops-using-recursion.english.md
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store-multiple-values-in-one-variable-using-javascript-arrays.english.md
storing-values-with-the-assignment-operator.english.md
subtract-one-number-from-another-with-javascript.english.md
testing-objects-for-properties.english.md
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understanding-undefined-value-returned-from-a-function.english.md
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updating-object-properties.english.md
use-bracket-notation-to-find-the-first-character-in-a-string.english.md
use-bracket-notation-to-find-the-last-character-in-a-string.english.md
use-bracket-notation-to-find-the-nth-character-in-a-string.english.md
use-bracket-notation-to-find-the-nth-to-last-character-in-a-string.english.md
use-conditional-logic-with-if-statements.english.md
use-multiple-conditional-ternary-operators.english.md
use-recursion-to-create-a-countdown.md
use-recursion-to-create-a-range-of-numbers.english.md
use-the-conditional-ternary-operator.english.md
use-the-parseint-function-with-a-radix.english.md
use-the-parseint-function.english.md
using-objects-for-lookups.english.md
word-blanks.english.md
write-reusable-javascript-with-functions.english.md
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89 lines
2.3 KiB
Markdown
89 lines
2.3 KiB
Markdown
---
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id: 56bbb991ad1ed5201cd392cc
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title: Manipulate Arrays With pop()
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challengeType: 1
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videoUrl: 'https://scrimba.com/c/cRbVZAB'
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forumTopicId: 18236
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---
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## Description
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<section id='description'>
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Another way to change the data in an array is with the <code>.pop()</code> function.
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<code>.pop()</code> 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, <code>.pop()</code> removes the last element from an array and returns that element.
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Any type of entry can be "popped" off of an array - numbers, strings, even nested arrays.
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```js
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var threeArr = [1, 4, 6];
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var oneDown = threeArr.pop();
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console.log(oneDown); // Returns 6
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console.log(threeArr); // Returns [1, 4]
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```
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</section>
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## Instructions
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<section id='instructions'>
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Use the <code>.pop()</code> function to remove the last item from <code>myArray</code>, assigning the "popped off" value to <code>removedFromMyArray</code>.
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</section>
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## Tests
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<section id='tests'>
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```yml
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tests:
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- text: <code>myArray</code> should only contain <code>[["John", 23]]</code>.
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testString: assert((function(d){if(d[0][0] == 'John' && d[0][1] === 23 && d[1] == undefined){return true;}else{return false;}})(myArray));
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- text: You should use <code>pop()</code> on <code>myArray</code>.
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testString: assert(/removedFromMyArray\s*=\s*myArray\s*.\s*pop\s*(\s*)/.test(code));
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- text: <code>removedFromMyArray</code> should only contain <code>["cat", 2]</code>.
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testString: assert((function(d){if(d[0] == 'cat' && d[1] === 2 && d[2] == undefined){return true;}else{return false;}})(removedFromMyArray));
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```
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</section>
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## Challenge Seed
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<section id='challengeSeed'>
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<div id='js-seed'>
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```js
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// Example
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var ourArray = [1,2,3];
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var removedFromOurArray = ourArray.pop();
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// removedFromOurArray now equals 3, and ourArray now equals [1,2]
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// Setup
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var myArray = [["John", 23], ["cat", 2]];
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// Only change code below this line.
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var removedFromMyArray;
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```
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</div>
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### After Test
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<div id='js-teardown'>
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```js
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(function(y, z){return 'myArray = ' + JSON.stringify(y) + ' & removedFromMyArray = ' + JSON.stringify(z);})(myArray, removedFromMyArray);
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```
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</div>
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</section>
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## Solution
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<section id='solution'>
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```js
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var myArray = [["John", 23], ["cat", 2]];
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var removedFromMyArray = myArray.pop();
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```
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</section>
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