[removed] Make an array of value pairs form an array of values

Question

Is there an elegant, functional way to turn this array:

[ 1, 5, 9, 21 ]

into this

[ [1, 5], [5, 9], [9, 21] ]

I kn

Answer 1

I'm sure there is an elegant way, programmatically, but, mathematically I can't help seeing that each new pair has an index difference of 1 from the original array.

If you (later) have the need to turn your array [ 1, 5, 9, 21, 33 ] into [ [1, 9], [5, 21], [9, 33] ], you can use the fact that the difference between the indices is 2.

If you create code for the index difference of 1, extending this would be easy.