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								---
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								id: 587d78b2367417b2b2512b0f
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								title: Remove Items from an Array with pop() and shift()
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								challengeType: 1
							 
						 
					
						
							
								
									
										
										
										
											2019-08-05 09:17:33 -07:00 
										
									 
								 
							 
							
								
									
										 
								
							 
							
								 
							
							
								forumTopicId: 301165
							 
						 
					
						
							
								
									
										
										
										
											2021-01-13 03:31:00 +01:00 
										
									 
								 
							 
							
								
									
										 
								
							 
							
								 
							
							
								dashedName: remove-items-from-an-array-with-pop-and-shift
							 
						 
					
						
							
								
									
										
										
										
											2018-09-30 23:01:58 +01:00 
										
									 
								 
							 
							
								
							 
							
								 
							
							
								---
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								
							 
						 
					
						
							
								
									
										
										
										
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								# --description--
  
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								Both `push()`  and `unshift()`  have corresponding methods that are nearly functional opposites: `pop()`  and `shift()` . As you may have guessed by now, instead of adding, `pop()`  *removes*  an element from the end of an array, while `shift()`  removes an element from the beginning. The key difference between `pop()`  and `shift()`  and their cousins `push()`  and `unshift()` , is that neither method takes parameters, and each only allows an array to be modified by a single element at a time.
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								
							 
						 
					
						
							
								
									
										
										
										
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								Let's take a look:
							 
						 
					
						
							
								
									
										
										
										
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								```js
							 
						 
					
						
							
								
									
										
										
										
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								let greetings = ['whats up?', 'hello', 'see ya!'];
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								greetings.pop();
							 
						 
					
						
							
								
									
										
										
										
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								```
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								`greetings`  would have the value `['whats up?', 'hello']` . 
						 
					
						
							
								
									
										
										
										
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								```js
							 
						 
					
						
							
								
									
										
										
										
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								greetings.shift();
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								```
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								
							 
						 
					
						
							
								
									
										
										
										
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								`greetings`  would have the value `['hello']` . 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								
							 
						 
					
						
							
								
									
										
										
										
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								We can also return the value of the removed element with either method like this:
							 
						 
					
						
							
								
									
										
										
										
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								```js
							 
						 
					
						
							
								
									
										
										
										
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								let popped = greetings.pop();
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								```
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								
							 
						 
					
						
							
								
									
										
										
										
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								`greetings`  would have the value `[]` , and `popped`  would have the value `hello` . 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								
							 
						 
					
						
							
								
									
										
										
										
											2020-11-27 19:02:05 +01:00 
										
									 
								 
							 
							
								
									
										 
								
							 
							
								 
							
							
								# --instructions--
  
						 
					
						
							
								
									
										
										
										
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								We have defined a function, `popShift` , which takes an array as an argument and returns a new array. Modify the function, using `pop()`  and `shift()` , to remove the first and last elements of the argument array, and assign the removed elements to their corresponding variables, so that the returned array contains their values.
							 
						 
					
						
							
								
									
										
										
										
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								# --hints--
  
						 
					
						
							
								
									
										
										
										
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								`popShift(["challenge", "is", "not", "complete"])`  should return `["challenge", "complete"]`  
						 
					
						
							
								
									
										
										
										
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								```js
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								assert.deepEqual(popShift(['challenge', 'is', 'not', 'complete']), [
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								  'challenge',
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								  'complete'
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								]);
							 
						 
					
						
							
								
									
										
										
										
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								```
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								
							 
						 
					
						
							
								
									
										
										
										
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								The `popShift`  function should utilize the `pop()`  method
							 
						 
					
						
							
								
									
										
										
										
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								```js
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								assert.notStrictEqual(popShift.toString().search(/\.pop\(/), -1);
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								```
							 
						 
					
						
							
								
									
										
										
										
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								The `popShift`  function should utilize the `shift()`  method
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								```js
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								assert.notStrictEqual(popShift.toString().search(/\.shift\(/), -1);
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								```
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								# --seed--
  
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								## --seed-contents--
  
						 
					
						
							
								
									
										
										
										
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								```js
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								function popShift(arr) {
							 
						 
					
						
							
								
									
										
										
										
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								  let popped; // Change this line
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								  let shifted; // Change this line
							 
						 
					
						
							
								
									
										
										
										
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								  return [shifted, popped];
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								}
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								console.log(popShift(['challenge', 'is', 'not', 'complete']));
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								```
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								
							 
						 
					
						
							
								
									
										
										
										
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								# --solutions--
  
						 
					
						
							
								
									
										
										
										
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								```js
							 
						 
					
						
							
								
									
										
										
										
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								function popShift(arr) {
							 
						 
					
						
							
								
									
										
										
										
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								  let popped = arr.pop(); // Change this line
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								  let shifted = arr.shift(); // Change this line
							 
						 
					
						
							
								
									
										
										
										
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								  return [shifted, popped];
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								}
							 
						 
					
						
							
								
									
										
										
										
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								```