How do I shuffle a list of lists?

September 8, 2022

I’ve got a list of lists:

myList = [[67, 79], [1, 5], [63, 122], [43, 44], [2, 5], [31, 37], [16, 45], [110, 124], [60, 64], [68, 79], [37, 116], [5, 76]]

And I would like to shuffle it around, but every way I’ve tried to do it has ruined the structure of lists and stripped it down to bare numbers. For instance:

myShuffledList = myList.sort((a, b) => 0.5 - Math.random());

Gives me something like:

myShuffledList = [60,64,110,124,63,122,5,76,43,44,68,79,37,116,2,5,1,5,67,79,16,45,31,37]

instead of something like this:

myShuffledList = [[68, 79], [2, 5], [31, 37], [1, 5], [67, 79], [110, 124], [63, 122], [16, 45], [5, 76], [37, 116], [43, 44], [60, 64]]

Is there simple solution as to how I can avoid the list being stripped completely, and just shuffle the lists of lists?

>Solution :

Everything is working as you intended it to. You just got bamboozled by console.log converting your array to strings. If you use a custom toString function to avoid this you can see that everything works as intended

myList = [
  [67, 79],
  [1, 5],
  [63, 122],
  [43, 44],
  [2, 5],
  [31, 37],
  [16, 45],
  [110, 124],
  [60, 64],
  [68, 79],
  [37, 116],
  [5, 76]
]
myShuffledList = myList.sort((a, b) => 0.5 - Math.random());

var toString = (list) => {
  return `${list.map((sublist) => `[${sublist}]`)}`
}

console.log(toString(myList))
console.log(toString(myShuffledList))