Dev-Feeds

is_a()

addr = Array.new
addr.is_a?Array #returns true

dd = 11 # which means tha month november
dd_end_txt = `date -d "#{mm}/1 + 1 month - 1day"`
# which returns "Sat Nov 30 00:00:00 IST 2013\n"
dummy = dd_end_txt.split(" ")
dd_end = dummy[2] if(dummy != nil)

# Result is 30

Method 1
arr = ["1","2",""]
arr.delete("")


Method 2
arr.reject! { |e| e.empty? }
 

Ruby
chars = ("a".."z").to_a + ("1".."100").to_a
random1 = Array.new(10, '').collect{chars[rand(chars.size)]}.join

Javascript:
var rand = Math.random() * 1000000000 * Math.random();
or
var rand = Math.random() * 1000000000


This is another efficient way to generate random number

<%= '&nbsp;' * 5 %>

Outputs:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

numeric_var  =~ /^[-+]?[0-9]*\.?[0-9]+$/

To get the current time:
time = Time.now

To get the current year:
year =  Time.now.Year

Search past 3 months records: 
Event.find(:all, :conditions => ["created_at > ? ",Time.now - 3.month])

This will create an array with the 10 empty elements.

>> Array.new(10, '')
Output
=> ["", "", "", "", "", "", "", "", "", ""]

To run the single migration in the db.

rake db:migrate       # Runs the full db migration
rake db:migrate VERSION=x #Runs the particular version

  dERs = Student.find(:all,:select => "id", :conditions => "")
  dER_ids = dERs.map(&:id)

cookies[:login] = { :value => "asdf", :expires => Time.now + 600} 

The above cookie will :expires in 10 min .

To Delete the Cookie in Ruby on rails:

cookies.delete :login 

To Delete Cookie in Javascript:

createCookie(":login","",-1); 

Create new controller in ruby on rails is the easy thing. Just follow the following process

[root]# script/generate controller <controller-name>

Sample
script/generate controller registration

this will genereate the following folders/files.

      exists  app/controllers/
      exists  app/helpers/
      create  app/views/registration
      exists  test/functional/
      create  app/controllers/registration_controller.rb
      create  test/functional/registration_controller_test.rb
      create  app/helpers/registration_helper.rb

Slicing the string or characters from the given start position with the given length of characters.

Look at the qucik example:

        dob = '10/13/1986'
        dob_mm = dob.slice(0,2)  #this returns 10
        dob_dd = dob.slice(2,2) #this returns 13
        dob_yy = dob.slice(4,4) #this returns 1986

Some of the predefined methods


"Worker".downcase #it returns "worker"
"worker".upcase #it returns "WORKER"
"worker".capitalize # this returns "Worker"


Capitalize function is very similar to the ucfirst() method in php.

Getting current time is very straight forward here.

The code is

Time.now # Returns Fri Mar 08 13:27:24 +0530 2013

Time.now.to_i # Returns the unix timestamp value 1362729785

gsub

gsub() is the always very useful function in ruby.

Syntax:

string.gsub("<search char>","<replace Char>")

        string.gsub(/'/,"") #replce/remove single quotes from the string


You should be careful that the string variable should not have a nil value. Otherwise it will rise a nil exception.