Ruby on Rails

prasannavigneshr · #1 10-09-2007, 01:48 AM

Installing Ruby and Rails

The installation process of Ruby and Rail on Windows, MAC and Linux are discussed detail in the following thread.

http://www.discussweb.com/ruby/4012-...s-windows.html

thanks

prasannavigneshr · #2 10-09-2007, 01:51 AM

Getting Started with Ruby

Ruby is the language that is going to make everything happen. To work with Ruby, you need a text editor of the kind you already used to get the Ruby on Rails example working, such as
word pad (Start➪ Programs➪Accessories➪WordPad) or
Notepad (Start➪Programs➪Accessories➪Notepad) in Windows.

Each Ruby program should be saved with the extension .rb

prasannavigneshr · #3 10-09-2007, 01:55 AM

Hello World in Ruby

To get started with Ruby and make it display a Hello World message, follow these steps:

Start your text editor and enter the following Ruby code:
Code:
```
puts “Hello World.”
```
Save the file as hello.rb. Make sure you save the file as a text file (select Text Document in the Save As Type drop-down), and if you are using windows WordPad or Notepad, make sure you enclose the name of the file in quotes—”hello.rb”—before saving to prevent those editors from saving the file as hello.rb.rtf or hello.rb.txt.
Use Ruby to run this new program and see the results. Just enter the ruby command followed by the name of the program at the command line:

C:\rubydev>ruby hello.rb

Hello World.

prasannavigneshr · #4 10-09-2007, 01:57 AM

Working with Numbers in RUBY

To get started with numbers in Ruby, follow these steps:

Enter this Ruby code in a new file:

Code:

puts 12345
puts 3.1415
puts 31415.0e-4
puts 12_345_678_987_654_321
puts 0xddff

Save the file as numbers.rb.
Use Ruby to run numbers.rb:

Quote:

C:\rubydev>ruby numbers.rb
12345
3.1415
3.1415
12345678987654321
56831

prasannavigneshr · #5 10-09-2007, 02:00 AM

Working with Strings in Ruby

To get started with strings in Ruby, follow these steps:

Enter this Ruby code in a new file, strings.rb:

Code:

puts “Hello”
puts “Hello “ + “there”
puts ‘Nice to see you.’
puts %Q/How are you?/
puts %Q!Fine, and you?!
puts %q!I’m also fine, thanks.!
puts “I have to say, ‘I am well.’”
puts “I’ll also say, \”Things are fine.\””

Save the file as strings.rb.
Run strings.rb using Ruby to see the result:

Quote:

C:\rubydev>ruby strings.rb
Hello
Hello there
Nice to see you.
How are you?
Fine, and you?
I’m also fine, thanks.
I have to say, ‘I am well.’
I’ll also say, “Things are fine.”

prasannavigneshr · #6 10-09-2007, 02:04 AM

Ruby’s reserved words:

__FILE
__ def
in
self
__LINE
__ defined?
module
super
BEGIN
do
next
then
END
else
nil
true
alias
elsif
not
undef
and
end
or
unless
begin
ensure
redo
until
break
false
rescue
when
case
for
retry
while
class
if
return
yield

prasannavigneshr · #7 10-09-2007, 02:07 AM

Storing Data in Variables - Working with Variables

To get started with variables in Ruby, follow these steps:

Enter this Ruby code in a new file, variables.rb:

Code:

temperature = 36
puts “The temperature is “ + String(temperature) + “.”
temperature = temperature + 5
puts “Now the temperature is “ + String(temperature) + “.”

Save the variables.rb file.
Run variables.rb to see the result:

Quote:

C:\rubydev>ruby variables.rb
The temperature is 36.
Now the temperature is 41.

prasannavigneshr · #8 10-09-2007, 02:14 AM

Creating Constants

You can also create constants in Ruby. A constant holds a value that you do not expect to change, such as

the value of pi:

PI = 3.1415926535

IP_SERVER_SOURCE = “903.111.333.055”
IP_SERVER_TARGET = “903.111.333.056”

Unlike other languages, Ruby allows you to change the values in constants by assigning a new value to
them:
CONST = 1
CONST = 2

However, you’ll get a warning each time you do this:

constants.rb:2: warning: already initialized constant CONST

prasannavigneshr · #9 10-09-2007, 02:16 AM

Interpolating Variables

To get started with interpolating expressions in double-quoted strings in Ruby, follow these steps:

Enter this code in a new file, doublequoted.rb:

Quote:

temperature = 36
puts “The temperature is #{temperature}.”
temperature = temperature + 5
puts “Now the temperature is #{temperature}.”
Save doublequoted.rb.
Run doublequoted.rb:

Quote:

C:\rubydev>ruby doublequoted.rb
The temperature is 36.
Now the temperature is 41.

prasannavigneshr · #10 10-09-2007, 02:19 AM

Reading Text

To get started reading text in Ruby, follow these steps:

Enter this code in a new file, gets.rb:

Quote:

print “Please enter the temperature: “
gets
chomp
puts “The temperature is #{$_}.”
Save the file and run it.
Ruby displays the prompt Please enter the temperature: and then waits for a response from you:

Quote:

C:\rubydev>ruby gets.rb
Please enter the temperature:
Enter a temperature and press Enter. Ruby reads the text that you have entered, chomps the
newline character off the end of it, and displays the resulting text:

Quote:

C:\rubydev>ruby gets.rb
Please enter the temperature: 36
The temperature is 36.

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