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Versions: 269
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Stored size: 1.25 KB
Contents
class Array
# Backport of Array#sample based on Marc-Andre Lafortune's https://github.com/marcandre/backports/
# Returns a random element or +n+ random elements from the array.
# If the array is empty and +n+ is nil, returns <tt>nil</tt>.
# If +n+ is passed and its value is less than 0, it raises an +ArgumentError+ exception.
# If the value of +n+ is equal or greater than 0 it returns <tt>[]</tt>.
#
# [1,2,3,4,5,6].sample # => 4
# [1,2,3,4,5,6].sample(3) # => [2, 4, 5]
# [1,2,3,4,5,6].sample(-3) # => ArgumentError: negative array size
# [].sample # => nil
# [].sample(3) # => []
def sample(n=nil)
return self[Kernel.rand(size)] if n.nil?
n = n.to_int
rescue Exception => e
raise TypeError, "Coercion error: #{n.inspect}.to_int => Integer failed:\n(#{e.message})"
else
raise TypeError, "Coercion error: obj.to_int did NOT return an Integer (was #{n.class})" unless n.kind_of? Integer
raise ArgumentError, "negative array size" if n < 0
n = size if n > size
result = Array.new(self)
n.times do |i|
r = i + Kernel.rand(size - i)
result[i], result[r] = result[r], result[i]
end
result[n..size] = []
result
end unless method_defined? :sample
end
Version data entries
269 entries across 225 versions & 25 rubygems