Follow Techotopia on Twitter

On-line Guides
All Guides
eBook Store
iOS / Android
Linux for Beginners
Office Productivity
Linux Installation
Linux Security
Linux Utilities
Linux Virtualization
Linux Kernel
System/Network Admin
Programming
Scripting Languages
Development Tools
Web Development
GUI Toolkits/Desktop
Databases
Mail Systems
openSolaris
Eclipse Documentation
Techotopia.com
Virtuatopia.com

How To Guides
Virtualization
General System Admin
Linux Security
Linux Filesystems
Web Servers
Graphics & Desktop
PC Hardware
Windows
Problem Solutions

  




 

 

Ruby Programming
Previous Page Home Next Page

Looking Inside Objects

Once you've found an interesting object, you may be tempted to find out just what it can do. Unlike static languages, where a variable's type determines its class, and hence the methods it supports, Ruby supports liberated objects. You really cannot tell exactly what an object can do until you look under its hood.[Or under its bonnet, for objects created to the east of the Atlantic.]

For instance, we can get a list of all the methods to which an object will respond.

r = 1..10 # Create a Range object
list = r.methods
list.length 60
list[0..3] ["size", "end", "length", "exclude_end?"]

Or, we can check to see if an object supports a particular method.

r.respond_to?("frozen?") true
r.respond_to?("hasKey") false
"me".respond_to?("==") true

We can determine our object's class and its unique object id, and test its relationship to other classes.

num = 1
num.id 3
num.class Fixnum
num.kind_of? Fixnum true
num.kind_of? Numeric true
num.instance_of? Fixnum true
num.instance_of? Numeric false

Ruby Programming
Previous Page Home Next Page

 
 
  Published under the terms of the Open Publication License Design by Interspire