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Array.distinct

distincton

Group: Selections
Aliases: deduplicate, unique

Documentation​

Keeps only unique elements within the array, removing any duplicates.

The returned unique elements are kept in the same order as they appeared in the input. Out of multiple equivalent (equal up to the on projection) elements, always the one appearing first in the input is kept.

Arguments​

  • on: A projection from the element type to the value of that element which determines the uniqueness criteria.

Examples​

Removing repeating entries.​

      [1, 3, 1, 2, 2, 1].to_array . distinct == [1, 3, 2].to_array

Keeping only pairs whose first elements are unique.​

      [Pair 1 "a", Pair 2 "b", Pair 1 "c"].to_array . distinct (on = _.first) == [Pair 1 "a", Pair 2 "b"].to_array