90 lines
2.3 KiB
Markdown
90 lines
2.3 KiB
Markdown
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---
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id: 56105e7b514f539506016a5e
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title: Count Backwards With a For Loop
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localeTitle: Contar hacia atrás con un bucle for
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challengeType: 1
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---
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## Description
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<section id='description'>
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A for loop también puede contar hacia atrás, siempre que podamos definir las condiciones correctas.
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Para contar hacia atrás de dos en dos, necesitaremos cambiar nuestra <code>initialization</code> , <code>condition</code> y <code>final-expression</code> .
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Comenzaremos en <code>i = 10</code> y haremos un bucle mientras <code>i > 0</code> . Disminuiremos <code>i</code> en 2 cada bucle con <code>i -= 2</code> .
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<blockquote>var ourArray = [];<br>for (var i=10; i > 0; i-=2) {<br> ourArray.push(i);<br>}</blockquote>
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<code>ourArray</code> ahora contendrá <code>[10,8,6,4,2]</code> .
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Cambiemos nuestra <code>initialization</code> y <code>final-expression</code> para que podamos contar hacia atrás de dos en dos con números impares.
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</section>
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## Instructions
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<section id='instructions'>
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Empuje los números impares del 9 al 1 a <code>myArray</code> usando un bucle <code>for</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: Usted debe estar usando una <code>for</code> bucle para esto.
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testString: 'assert(code.match(/for\s*\(/g).length > 1, "You should be using a <code>for</code> loop for this.");'
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- text: Deberías estar usando el método de matriz <code>push</code> .
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testString: 'assert(code.match(/myArray.push/), "You should be using the array method <code>push</code>.");'
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- text: ' <code>myArray</code> debe ser igual a <code>[9,7,5,3,1]</code> .'
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testString: 'assert.deepEqual(myArray, [9,7,5,3,1], "<code>myArray</code> should equal <code>[9,7,5,3,1]</code>.");'
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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 = [];
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for (var i = 10; i > 0; i -= 2) {
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ourArray.push(i);
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}
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// Setup
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var myArray = [];
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// Only change code below this line.
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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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console.info('after the test');
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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 ourArray = [];
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for (var i = 10; i > 0; i -= 2) {
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ourArray.push(i);
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}
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var myArray = [];
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for (var i = 9; i > 0; i -= 2) {
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myArray.push(i);
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}
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```
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</section>
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