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Last active October 29, 2023 01:41
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Shuffle Array - JavaScript ES2015, ES6
// original gist
const shuffleArray = arr => arr.sort(() => Math.random() - 0.5);
// fully random by @BetonMAN
const shuffleArray = arr => arr
.map(a => [Math.random(), a])
.sort((a, b) => a[0] - b[0])
.map(a => a[1]);
shuffleArray([1, 2, 3]) //[3, 1, 2]
@DutchKevv
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But still its missing one ;)

@guilhermepontes
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ty guys!

@stamster
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What about objects?

@BetonMAN
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BetonMAN commented Nov 29, 2017

Problem of this shuffle implementation is that it's not fully random. If you want really fully random shuffle, you need to use a code like this:

var array = [1,2,3,4,5,6,7,8,9];

var shuffled = array.map((a) => [Math.random(),a]).sort((a,b) => a[0]-b[0]).map((a) => a[1]);

For more information see this

@guilhermepontes
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@stamster wut?

@tigco
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tigco commented Apr 8, 2018

@BetonMAN, neat implementation! It seems that the only downside, comparing to the implementation from Wikipedia, is that "the time and space complexity of the sort cannot be guaranteed as it is implementation dependent." MDN Array.sort . It is O(n) in the implementation of Fisher–Yates shuffle on Wikipedia .

@Aqua-Dream
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Remember that the time complexity of sorting an array with length n is theta(n*log(n)), but the common shuffle algorithm takes theta(n). If the array is long, try to avoid sorting.

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