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---
id: 56105e7b514f539506016a5e
title: Count Backwards With a For Loop
localeTitle: Contar hacia atrás con un bucle for
challengeType: 1
---
## Description
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< section id = 'description' >
A for loop también puede contar hacia atrás, siempre que podamos definir las condiciones correctas.
Para contar hacia atrás de dos en dos, necesitaremos cambiar nuestra < code > initialization< / code > , < code > condition< / code > y < code > final-expression< / code > .
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 > .
< blockquote > var ourArray = [];< br > for (var i=10; i > 0; i-=2) {< br > ourArray.push(i);< br > }< / blockquote >
< code > ourArray< / code > ahora contendrá < code > [10,8,6,4,2]< / code > .
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 >
## Instructions
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< section id = 'instructions' >
Empuje los números impares del 9 al 1 a < code > myArray< / code > usando un bucle < code > for< / code > .
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< / section >
## Tests
< section id = 'tests' >
```yml
tests:
- text: Usted debe estar usando una < code > for</ code > bucle para esto.
testString: 'assert(code.match(/for\s*\(/g).length > 1, "You should be using a < code > for</ code > loop for this.");'
- text: Deberías estar usando el método de matriz < code > push</ code > .
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 > .");'
```
< / section >
## Challenge Seed
< section id = 'challengeSeed' >
< div id = 'js-seed' >
```js
// Example
var ourArray = [];
for (var i = 10; i > 0; i -= 2) {
ourArray.push(i);
}
// Setup
var myArray = [];
// Only change code below this line.
```
< / div >
### After Test
< div id = 'js-teardown' >
```js
console.info('after the test');
```
< / div >
< / section >
## Solution
< section id = 'solution' >
```js
var ourArray = [];
for (var i = 10; i > 0; i -= 2) {
ourArray.push(i);
}
var myArray = [];
for (var i = 9; i > 0; i -= 2) {
myArray.push(i);
}
```
< / section >