Question

Is it possible to clearly identify a class of variable?

something like:

@users.who_r_u? #=>Class (some information)

@packs.who_r_u? #=> Array (some information)

etc.

Can someone provide clear short explanation of difference between Class, Hash, Array, Associated Array, etc. ?

Answer 1

You can use:

@users.class

Test it in irb:

1.9.3p0 :001 > 1.class
 => Fixnum 
1.9.3p0 :002 > "1".class
 => String
1.9.3p0 :003 > [1].class
 => Array 
1.9.3p0 :004 > {:a => 1}.class
 => Hash 
1.9.3p0 :005 > (1..10).class
 => Range 

Or:

1.9.3p0 :010 > class User
1.9.3p0 :011?>   end
 => nil 
1.9.3p0 :012 > @user = User.new
 => #<User:0x0000010111bfc8> 
1.9.3p0 :013 > @user.class
 => User 

These were only quick irb examples, hope it’s enough to see the use of .class in ruby.