Unflatten

Unflatten[flatList, listyList]⟹out

restructures the flat list flatList so it has the same structure as listyList.

Unflatten[flatList, listyList, pattern]⟹out

assumes listyList is a nested list containing only things that MatchQ with pattern.

Details

Unflatten into rectangular array:

Unflatten into jagged array:

Unflatten symbols based on integer skeleton:

Unflatten higher dimensional rectangular array: