|
1.1 What is Ruby? |
Ruby
is a pure object-oriented programming language with a super clean
syntax that makes programming elegant and fun. Ruby successfully
combines Smalltalk's conceptual elegance, Python's ease of use and
learning, and Perl's pragmatism. Ruby originated in Japan in the early
1990s, and has started to become popular worldwide in the past few
years as more English language books and documentation have become
available. |
|
1.2 What is Rails? |
Rails
is an open source Ruby framework for developing database-backed web
applications. What's special about that? There are dozens of frameworks
out there and most of them have been around much longer than Rails. Why
should you care about yet another framework? What would you think if I
told you that you could develop a web application at least ten times
faster with Rails than you could with a typical Java framework? You
can--without making any sacrifices in the quality of your application!
How is this possible? Part of the answer is in the Ruby programming
language. Many things that are very simple to do in Ruby are not even
possible in most other languages. Rails takes full advantage of this.
The rest of the answer is in two of Rail's guiding principles: less
software and convention over configuration. Less software means you
write fewer lines of code to implement your application. Keeping your
code small means faster development and fewer bugs, which makes your
code easier to understand, maintain, and enhance. Very shortly, you
will see how Rails cuts your code burden. Convention over configuration
means an end to verbose XML configuration files--there aren't any in
Rails! Instead of configuration files, a Rails application uses a few
simple programming conventions that allow it to figure out everything
through reflection and discovery. Your application code and your
running database already contain everything that Rails needs to know! |
|
|
1.3 How to capitalize UTF8 string without downcasing |
| What is the best way to capitalize the first character of a UTF8 string?
String#capitalize downcases the rest of the string which is unacceptable
since there can be capitals in the middle of the string. ("see New
York".capitalize => "See new york"). Just picking off the first byte and
capitalizing that is also not an option since the first character can be
a multibyte UTF-8 character.
The only thing I can think of so far is either using Ruby 1.9 or the the
Rails multibyte Chars library to split off the first character and then
capitalize that and join it back together.
Surely there must be a better way for such a common problem? |
|
1.4 What is the naming conventions for methods that return a boolean result? |
| Methods
that return a boolean result are typically named with a ending question
mark. For example: def active? return true #just always returning true
end |
| 1.5 What are the object-oriented programming features supported by Ruby? |
| Classes,Objects,Inheritance,Singleton
methods,polymorphism(accomplished by over riding and overloading) are
some oo concepts supported by ruby. ... |
| 1.6 What are the operating systems supported by Ruby? |
| Windows and linux operating systems are supported by the Ruby |
| 1.7 Whats the difference between symbol and string?
|
Symbol refers to the same memory location where string
generates a new id every time for eg.
STRING
irb(main):019:0> "ruby".object_id
=> 24095860
irb(main):020:0> "ruby".object_id
=> 24092310
irb(main):021:0> "ruby".object_id
=> 24088760
irb(main):022:0>
SYMBOL
irb(main):022:0> :ruby.object_id
=> 102978
irb(main):023:0> :ruby.object_id
=> 102978
irb(main):024:0> :ruby.object_id
=> 102978
irb(main):025:0> :ruby.object_id
=> 102978
irb(main):026:0>
|
|
1.8 How do you comment out a block of code? |
Use =begin and =end. =begin def
my_commented_out_method end =end
You could use successive # signs, but that's just tedious: # # def my commented_out_method # end # |
| 1.9 How would you create a new ruby rail application? |
| To create a new ruby rail application rails my_app cd my_app |
| 1.10 What is the difference between nil and false in ruby? |
| False is a boolean datatype Nil is not a data type |
| 1.11 What two delimiters are used for blocks? |
| Curly
braces {...} and "do"..."end" Bonus: coding convention is to use curly
braces if the code will fit on one line and "do"..."end" syntax if the
block contains multiple lines. |
| 1.12 What is the naming conventions for methods that return a boolean result? |
| Methods
that return a boolean result are typically named with a ending question
mark. For example: def active? return true #just always returning true
end |
| 1.13 Explain about the programming language ruby? |
Ruby
is the interpreted scripting language for quick and easy
object-oriented programming. It has many features to process text files
and to do system management tasks (as in Perl). It is simple,
straight-forward, extensible, and portable.
Oh, I need to mention, it's totally free, which means not only free of
charge, but also freedom to use, copy, modify, and distribute it.
Features of Ruby
* Ruby has simple syntax, partially inspired by Eiffel and Ada.
* Ruby has exception handling features, like Java or Python, to make it easy to handle errors.
* Ruby's operators are syntax sugar for the methods. You can redefine them easily.
* Ruby is a complete, full, pure object oriented language: OOL. This
means all data in Ruby is an object, in the sense of Smalltalk: no
exceptions. Example: In Ruby, the number 1 is an instance of class
Fixnum.
* Ruby's OO is carefully designed to be both complete and open for
improvements. Example: Ruby has the ability to add methods to a class,
or even to an instance during runtime. So, if needed, an instance of
one class *can* behave differently from other instances of the same
class.
* Ruby features single inheritance only, *on purpose*. But Ruby knows
the concept of modules (called Categories in Objective-C). Modules are
collections of methods. Every class can import a module and so gets all
its methods for free. Some of us think that this is a much clearer way
than multiple inheritance, which is complex, and not used very often
compared with single inheritance (don't count C++ here, as it has often
no other choice due to strong type checking!).
* Ruby features true closures. Not just unnamed function, but with present variable bindings.
* Ruby features blocks in its syntax (code surrounded by '{' ... '}' or
'do' ... 'end'). These blocks can be passed to methods, or converted
into closures.
* Ruby features a true mark-and-sweep garbage collector. It works with
all Ruby objects. You don't have to care about maintaining reference
counts in extension libraries. This is better for your health. ;-)
* Writing C extensions in Ruby is easier than in Perl or Python, due
partly to the garbage collector, and partly to the fine extension API.
SWIG interface is also available.
* Integers in Ruby can (and should) be used without counting their
internal representation. There *are* small integers (instances of class
Fixnum) and large integers (Bignum), but you need not worry over which
one is used currently. If a value is small enough, an integer is a
Fixnum, otherwise it is a Bignum. Conversion occurs automatically.
* Ruby needs no variable declarations. It uses simple naming
conventions to denote the scope of variables. Examples: simple 'var' =
local variable, '@var' = instance variable, '$var' = global variable.
So it is also not necessary to use a tiresome 'self.' prepended to
every instance member.
* Ruby can load extension libraries dynamically if an OS allows.
* Ruby features OS independent threading. Thus, for all platforms on
which Ruby runs, you also have multithreading, regardless of if the OS
supports it or not, even on MS-DOS! ;-)
* Ruby is highly portable: it is developed mostly on Linux, but works
on many types of UNIX, DOS, Windows 95/98/Me/NT/2000/XP, MacOS, BeOS,
OS/2, etc.
|
| 1.14 Why Ruby on Rails? |
1)for fast developing websites
2)convention over configuration
3)scaffolding
4)pure Object oriented concepts
5)less coding
6)easy understanding of coding
7)follows MVC architecture
8)using library and gem files |
