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							|  |  |  | id: 56105e7b514f539506016a5e | 
					
						
							|  |  |  | title: Count Backwards With a For Loop | 
					
						
							|  |  |  | challengeType: 1 | 
					
						
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											2019-02-14 12:24:02 -05:00
										 |  |  | videoUrl: 'https://scrimba.com/c/c2R6BHa' | 
					
						
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											2019-07-31 11:32:23 -07:00
										 |  |  | forumTopicId: 16808 | 
					
						
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											2021-01-13 03:31:00 +01:00
										 |  |  | dashedName: count-backwards-with-a-for-loop | 
					
						
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											2018-09-30 23:01:58 +01:00
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										 |  |  | # --description--
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										 |  |  | A for loop can also count backwards, so long as we can define the right conditions. | 
					
						
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											2021-01-21 10:44:10 -06:00
										 |  |  | In order to decrement by two each iteration, we'll need to change our `initialization`, `condition`, and `final-expression`. | 
					
						
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							|  |  |  | We'll start at `i = 10` and loop while `i > 0`. We'll decrement `i` by 2 each loop with `i -= 2`. | 
					
						
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											2019-05-17 06:20:30 -07:00
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							|  |  |  | ```js | 
					
						
							|  |  |  | 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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										 |  |  | `ourArray` will now contain `[10,8,6,4,2]`. Let's change our `initialization` and `final-expression` so we can count backward by twos by odd numbers. | 
					
						
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											2020-11-27 19:02:05 +01:00
										 |  |  | # --instructions--
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										 |  |  | Push the odd numbers from 9 through 1 to `myArray` using a `for` loop. | 
					
						
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										 |  |  | # --hints--
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										 |  |  | You should be using a `for` loop for this. | 
					
						
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										 |  |  | ```js | 
					
						
							|  |  |  | assert(/for\s*\([^)]+?\)/.test(code)); | 
					
						
							|  |  |  | ``` | 
					
						
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										 |  |  | You should be using the array method `push`. | 
					
						
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							|  |  |  | ```js | 
					
						
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										 |  |  | assert(code.match(/myArray.push/)); | 
					
						
							|  |  |  | ``` | 
					
						
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										 |  |  | `myArray` should equal `[9,7,5,3,1]`. | 
					
						
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										 |  |  | ```js | 
					
						
							|  |  |  | assert.deepEqual(myArray, [9, 7, 5, 3, 1]); | 
					
						
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										 |  |  | ``` | 
					
						
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										 |  |  | # --seed--
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										 |  |  | ## --after-user-code--
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							|  |  |  | ```js | 
					
						
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										 |  |  | if(typeof myArray !== "undefined"){(function(){return myArray;})();} | 
					
						
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										 |  |  | ``` | 
					
						
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										 |  |  | ## --seed-contents--
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										 |  |  | ```js | 
					
						
							|  |  |  | // Setup | 
					
						
							|  |  |  | var myArray = []; | 
					
						
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										 |  |  | // Only change code below this line | 
					
						
							|  |  |  | ``` | 
					
						
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										 |  |  | # --solutions--
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							|  |  |  | ```js | 
					
						
							|  |  |  | var myArray = []; | 
					
						
							|  |  |  | for (var i = 9; i > 0; i -= 2) { | 
					
						
							|  |  |  |   myArray.push(i); | 
					
						
							|  |  |  | } | 
					
						
							|  |  |  | ``` |