Class: Numeric (Ruby 2.5.0)

Home » How To Check For Value Greater Than 1 In Ruby » Class: Numeric (Ruby 2.5.0)

Maybe your like

Numeric is the class from which all higher-level numeric classes should inherit.

Numeric allows instantiation of heap-allocated objects. Other core numeric classes such as Integer are implemented as immediates, which means that each Integer is a single immutable object which is always passed by value.

a = 1 1.object_id == a.object_id #=> true

There can only ever be one instance of the integer 1, for example. Ruby ensures this by preventing instantiation and duplication.

Integer.new(1) #=> NoMethodError: undefined method `new' for Integer:Class 1.dup #=> TypeError: can't dup Integer

For this reason, Numeric should be used when defining other numeric classes.

Classes which inherit from Numeric must implement coerce, which returns a two-member Array containing an object that has been coerced into an instance of the new class and self (see coerce).

Inheriting classes should also implement arithmetic operator methods (+, -, * and /) and the <=> operator (see Comparable). These methods may rely on coerce to ensure interoperability with instances of other numeric classes.

class Tally < Numeric def initialize(string) @string = string end def to_s @string end def to_i @string.size end def coerce(other) [self.class.new('|' * other.to_i), self] end def <=>(other) to_i <=> other.to_i end def +(other) self.class.new('|' * (to_i + other.to_i)) end def -(other) self.class.new('|' * (to_i - other.to_i)) end def *(other) self.class.new('|' * (to_i * other.to_i)) end def /(other) self.class.new('|' * (to_i / other.to_i)) end end tally = Tally.new('||') puts tally * 2 #=> "||||" puts tally > 1 #=> true

Tag » How To Check For Value Greater Than 1 In Ruby