method
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-(p1)
public
Array Difference
Returns a new array that is a copy of the original array, removing any items that also appear in other_ary. The order is preserved from the original array.
It compares elements using their #hash and #eql? methods for efficiency.
[ 1, 1, 2, 2, 3, 3, 4, 5 ] - [ 1, 2, 4 ] #=> [ 3, 3, 5 ]
If you need set-like behavior, see the library class Set.