a-b: is the elements of a except for those also in b : Set « Collections « Ruby






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a-b: is the elements of a except for those also in b


require 'set'

primes = Set[2, 3, 5, 7]
odds = Set[1, 3, 5, 7, 9]

p primes-odds               # => #<Set: {2}>
p odds-primes               # => #<Set: {1, 9}>
p primes.difference(odds)   # A named method alias








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