Ruby/Number/Integer
Материал из Wiki.crossplatform.ru
An integer with the kind_of? method (this method is from the Object class).
# Integer honors the 0 (octal), 0b (binary), and 0x (hexadecimal) prefixes. x = 100 x.kind_of? Integer # => true
Basic Math Operations for integer
puts 7 + 5 # add puts 20 - 8 # subtract puts 2 * 6 # multiply puts 144 / 12 # divide puts 12**2 # exponent puts 12 % 5 # modulo (remainder of division)
Change x from an integer to a floating point with the to_f method from the Fixnum class
x = 100 x.to_f # => 100.0
Comparison Methods
puts 1 > 2 puts 1 < 2 # false # true puts 5 >= 5 puts 5 <= 4 # true # false puts 1 == 1 puts 2 != 1 # true # true puts "cat" < "dog" # true
difference between "puts x / y" and "puts x.to_f / y.to_f"
x = 10 y = 3 puts x / y puts x.to_f / y.to_f
General Predicates
puts 0.zero? # => true (is this number zero?) puts 1.0.zero? # => false puts 0.0.nonzero? # => nil (works like false) puts 1.nonzero? # => 1 (works like true) puts 1.integer? # => true puts 1.0.integer? # => false puts 1.scalar? # => false: not a complex number. Ruby 1.9. puts 1.0.scalar? # => false: not a complex number. Ruby 1.9.
Integer and Float
# numbers without decimal points are called integers # numbers with decimal points are usually called floating-point numbers, or more simply, floats. # Here are some integers: 5 -205 9999999999999999999999999 0 # And here are some floats: 54.321 0.001 -205.3884 0.0
Integer is an instance of the Fixnum class, which inherits the Integer class.
x = 100 x.class # => Fixnum
Integer predicates
puts 0.even? # => true (Ruby 1.9) puts 0.odd? # => false
List the modules which Integer class is from
p Integer.included_modules # => [Precision, Comparable, Kernel]
puts 120.chr
puts 120.chr
to integers, using to_i:
puts 5.7.to_i
