Rails console


#1

I tried to create an addition to Enumerable called choose_randomly
that picks a random element from the Enumerable object. However when I
define it and execute the code rand complains about the wrong number
of arguments. Below is a capture of the ./script/console session.

farrel@nicodemus ~/Work/GreenGreen/Code/green_green_client_application
$ ./script/console
Loading development environment (Rails 2.1.2)

[1,2,3].choose_randomly
NoMethodError: undefined method `choose_randomly’ for [1, 2, 3]:Array
from (irb):1

module Enumerable
def choose_randomly
array_of_self = Array( self )
index = rand( array_of_self.size )
array_of_self[ index ]
end
end
=> nil

[1,2,3].choose_randomly
ArgumentError: wrong number of arguments (1 for 0)
from (irb):5:in rand' from (irb):5:inchoose_randomly’
from (irb):9

[1,2,3][ rand( [1,2,3].size )]
=> 1

As you can see if I execute the code myself it seems to work. If I
copy that same code into irb it works perfectly.

Any ideas?

Farrel


#2

On 30 Oct 2008, at 16:22, Farrel wrote:

As you can see if I execute the code myself it seems to work. If I
copy that same code into irb it works perfectly.

You’re calling Array#rand (a private method Array defines), whereas
you want to call Kernel#rand. Replace rand with Kernel.rand and you
should be ok

Fred


#3

On Oct 30, 7:05 pm, Frederick C. removed_email_address@domain.invalid
wrote:

You’re calling Array#rand (a private method Array defines), whereas
you want to call Kernel#rand. Replace rand with Kernel.rand and you
should be ok

That was it. Thanks for the tip. I didn’t know Rails added in it’s own
rand method into Array.

Farrel