ruby send method passing multiple parameters
RubyRuby Problem Overview
Trying to create objects and call methods dynamically by
Object.const_get(class_name).new.send(method_name,parameters_array)
which is working fine when
Object.const_get(RandomClass).new.send(i_take_arguments,[10.0])
but throwing wrong number of arguments 1 for 2 for
Object.const_get(RandomClass).new.send(i_take_multiple_arguments,[25.0,26.0])
The Random Class defined is
class RandomClass
def i_am_method_one
puts "I am method 1"
end
def i_take_arguments(a)
puts "the argument passed is #{a}"
end
def i_take_multiple_arguments(b,c)
puts "the arguments passed are #{b} and #{c}"
end
end
Can someone help me on how to send mutiple parameters to a ruby method dynamically
Ruby Solutions
Solution 1 - Ruby
send("i_take_multiple_arguments", *[25.0,26.0]) #Where star is the "splat" operator
or
send(:i_take_multiple_arguments, 25.0, 26.0)
Solution 2 - Ruby
You can alternately call send
with it's synonym __send__
:
r = RandomClass.new
r.__send__(:i_take_multiple_arguments, 'a_param', 'b_param')
By the way* you can pass hashes as params comma separated like so:
imaginary_object.__send__(:find, :city => "city100")
or new hash syntax:
imaginary_object.__send__(:find, city: "city100", loc: [-76, 39])
According to Black, __send__
is safer to namespace.
> “Sending is a broad concept: email is sent, data gets sent to I/O sockets, and so forth. It’s not uncommon for programs to define a method called send that conflicts with Ruby’s built-in send method. Therefore, Ruby gives you an alternative way to call send: __send__
. By convention, no one ever writes a method with that name, so the built-in Ruby version is always available and never comes into conflict with newly written methods. It looks strange, but it’s safer than the plain send version from the point of view of method-name clashes”
Black also suggests wrapping calls to __send__
in if respond_to?(method_name)
.
if r.respond_to?(method_name)
puts r.__send__(method_name)
else
puts "#{r.to_s} doesn't respond to #{method_name}"
end
Ref: Black, David A. The well-grounded Rubyist. Manning, 2009. P.171.
*I came here looking for hash syntax for __send__
, so may be useful for other googlers. ;)