class Array
# returns a random element of the array
def rand
self[Kernel.rand(length)]
end
end
class Hash
# returns a random key-value pair
def rand
temp_key = self.keys.rand
[temp_key, self[temp_key]]
end
end
module Kernel
# random_n_digit_number(1) returns a number between 1 and 9 inclusive
# random_n_digit_number(3) returns a number between 100 and 999 inclusive
def random_n_digit_number(n)
raise ArgumentError, "expected digit length to be greater or equal to 1, received #{n.inspect}" if !n.is_a?(Numeric) || n < 1
return rand(10) if n == 1
min = 10**(n-1)
max = (10**n)-1
rand(max-min+1) + min
end
end
class Range
# (1..10).rand returns a number between 1 and 10 inclusive
# (1...10).rand returns a number between 1 and 9 inclusive
# (2..2).rand returns 2
# (2...2).rand is equivalent to 2 + Kernel.rand()
# (Date.parse('2008-08-01')..Date.parse('2008-08-31')).rand returns a date between the first and last dates
inclusive
# (Time.now..(Time.now+60)).rand returns a time between the first and last times inclusive
def rand
self.first + Kernel.rand(self.last - self.first + (self.exclude_end? ? 0 : 1))
end
end
>> a = [1,2,3,4,5,6,7,8,9,10]
=> [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
>> Hash[ *a ]
=> {5=>6, 1=>2, 7=>8, 3=>4, 9=>10}
>>
?> b = [ [1,2], [3,4], 5, 6, 7, 8, 9, 10 ]
=> [[1, 2], [3, 4], 5, 6, 7, 8, 9, 10]
>> Hash[ *b ]
=> {5=>6, [1, 2]=>[3, 4], 7=>8, 9=>10}
# Requires Ruby 1.8.7 or higher.
>> keys = [1,2,[3,4]]
=> [1, 2, [3, 4]]
>> values = ['a','b',['c','d']]
=> ["a", "b", ["c", "d"]]
>> Hash[ * keys.zip(values).flatten(1) ]
=> {1=>;"a", [3, 4]=>["c", "d"], 2=>"b"}
# Seeing things like "<Date: 4909275/2,0,2299161>" in logs gives no immediate
# clue what that date is. Now one can use Date.new_from_inspect to see what date the
# inspect string represents.
>> Date.new_from_inspect('#<Date: 4909275/2,0,2299161>').to_s
=> "2008-06-20"
>> Date.new_from_inspect(Date.today.inspect) == Date.today
=> true
class Date
def self.new_from_inspect(date_inspect_string)
args = date_inspect_string.split(/[^\d]/).reject{|s| s.empty?}.map{|s| s.to_i}
new!( Rational(*args.first(2)), *args.last(2) )
end
end