What methods do we have to get a shuffle of a list of items?

Lounge (Discussions)
4

Daaaaaang. Bringing Pi into the mix is tasty! I'll need to study that one more.

I also love @steve_ssh 's idea to sort a bunch of random values and shuffle in one swing, taking the original values along for the ride.

Here's my quick'n'dirty stab:

While ([
	~vals = "1¶2¶3¶4¶5¶6¶7¶8¶9" ;
	~len = ValueCount ( ~vals  ) ;
	~res = ""
];
~len > 0 ;
[
	// get a random 1-based idx within remaining range
	~idx = Ceiling ( random * ~len ) ;

	// pluck out the value
	~val = GetValue ( ~vals ; ~idx ) ;
	~vals = LeftValues ( ~vals ; ~idx - 1 ) & RightValues ( ~vals ; ~len - ~idx ) ;
	~len = ~len - 1 ;

	// append it to the result
	~res = list ( ~res ; ~val )
];
~res
)

And here's a comparably quick'n'dirty visual of the algo

Screenshot 2023-11-03 at 11.29.50 PM
Screenshot 2023-11-03 at 11.29.50 PM1440×1578 177 KB

EDIT: After eyeballing my picture above, I realized you could feasibly shuffle "in place" (though I think FM lacks the ability to do that efficiently under the hood), by appending the plucked value to the end of ~vals and still decrement ~len on each iteration.

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