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Feature #9808
closedEnumerable#argmin_by, #argmax_by
Status:
Rejected
Assignee:
-
Target version:
-
Description
What about introducing Enumerable
#argmin_by
(and #argmax_by
too, of course) method?
Use cases are wide from mathematical problems to a general tasks. Here are two very simple examples:
(1..2).step(0.01).argmin_by{|x| Math.sin(x)*x}
queues = [[],[],[],[]]
# ...
least_busy_queue = queues.argmin_by{|queue| queues.size }
least_busy_queue << new_task
For cases when #argmin_by
isn't enough because one need to obtain index of minimal element I suggest #index_min_by
method which returns index of element for which block yields minimal value. It prevents user from using ineffective but straight two-pass algorithm like arr.index(arr.min)
:
# guess the number game
hidden_number = rand(100)
player_answers = 5.times.map{ gets.to_i }
best_player = player_answers.index_min_by{|answer| (answer-hidden_number).abs}
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