UniqueElements¶

Given a list of lists, returns for each list the elements that are unique to it (i.e. that appear in that list but in none of the others). Duplicates within a list are removed and the first-appearance order is preserved.

$ wo 'UniqueElements[{{1, 2, 3, 4, 5}, {3, 4, 5, 6, 7}}]'
{{1, 2}, {6, 7}}

$ wo 'UniqueElements[{{1, 2, 2, b, b, a}, {4, 3, 2, 1}}]'
{{b, a}, {4, 3}}

$ wo 'UniqueElements[{{1, 2, 3, 4}, {2, 3, 4, 5}, {3, 4, 5, 6}}]'
{{1}, {}, {6}}

An optional test function decides when two elements are considered equivalent:

$ wo 'UniqueElements[{{1, 2}, {4, 6}}, Mod[#1, 3] == Mod[#2, 3] &]'
{{2}, {6}}