Ruby Math.radians

I need Math.radians() function and canno开发者_如何学Got find it.

radians=(angle/180)* Math::PI

You probably want to create a file called "mymath.rb" in the lib/ directory, and monkey patch Math, like this:

require 'mathn'
module Math
  def self.to_rad angle
    angle / 180.0 * Math::PI
  end
end

or you can do what @MBO said in his comment. The link seems to be down, but the Google archives yield this informative little sentence, which indicates a solution that may be cleaner than mine (though I prefer keeping math stuff inside of math):

The simplest solution is to define a conversion method in Numeric that will convert a number of degrees into radians.

As a note, Ruby 2.0 has a feature called "Refinement" that basically lets you do local monkey-patching. It works this way (lifted from this blog post :

module RadiansConversion
  refine Math do
    def to_rad angle
      angle / 180.0 * Math::PI
    end
  end
end

And then .... It's available inside another module or anything such like that.

module MyApp
  using RadiansConversion

  p Math.to_rad 180   #=> 3.14159265358979
  p Math.to_rad 235   #=> 4.10152374218667
end

Or you could extend Float to add a 'to_rad' convertion:

class Float
 def to_rad
   self/180 * Math::PI
  end
end

And use it like this

radian=angle.to_rad

EDIT (because of down voting): Sorry! The time I answered, I needed this for an array of values and just wanted to share what I found.

So, yes actually it is just:

x * (Math::PI / 180)

Just wanted to show an implementation I found.

# Geocoder::Calculations.to_radians(@geocode)
def to_radians(*args)
  args = args.first if args.first.is_a?(Array)
  if args.size == 1
    args.first * (Math::PI / 180)
  else
    args.map{ |i| to_radians(i) }
  end
end

Convert degrees to radians. If an array (or multiple arguments) is passed, converts each value and returns array.

http://rubydoc.info/github/alexreisner/geocoder/master/Geocoder/Calculations#to_radians-instance_method