ruby-list 39588 からのスレッドより
Simple に
class Array
def randomize
sort_by{ rand(100) }
end
def randomize!
replace randomize
end
end
速度を気にする場合
class Array
def randomize!
length.times do |i1|
i2 = rand(length)
t = self[i1]
self[i1] = self[i2]
self[i2] = t
end
end
def randomize
result = self.dup
result.randomize!
result
end
end