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SyunWatanabe/reimpliment_count.rb

Created February 20, 2020 01:09
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reimpliment_count.rb
# count 再実装
class Array
def count(*args)
if block_given?
num = 0
each { |i| num += 1 if yield(i) }
num
elsif args.empty?
size
else
num = 0
each { |i| num += 1 if i == args[0] }
num
end
end
end
puts [1, 2, 4, 2].count #=> 4
puts [1, 2, 4, 2].count(2) #=> 2
puts [1, 2, 4, 2].count(&:even?) #=> 3
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