Ruby/C3/Object-Oriented-Programming-Methods/Gujarati

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Time Narration
00:01 Ruby માં Object Oriented Programming – Methods પરનાં સ્પોકન ટ્યુટોરીયલમાં તમારુ સ્વાગત છે.
00:07 આ ટ્યુટોરીયલમાં આપણે શીખીશું :
00:09 * instance methods
00:11 * class methods
00:14 * accessor methods.
00:15 અહી આપણે વાપરી રહ્યા છીએ:
  • Ubuntu version 12.04
00:19 * Ruby 1.9.3
00:22 આ ટ્યુટોરીયલ ના અનુસરણ માટે તમારી પાસે કાર્ય કરતું Internet કનેક્શન હોવું જોઈએ.
00:27 તમને Linux commands, Terminal અને Text-editor. નું જ્ઞાન હોવું જોઈએ.
00:31 જો નથી, તો સંબંધિત ટ્યુટોરીયલો માટે, અમારી વેબસાઇટની મુલાકાત લો.
00:36 શરૂઆત કરવા પહેલા, યાદ કરો કે આપણે “ttt” નામની એક ડીરેક્ટરી પહેલા બનાવી હતી.
00:41 Let's go to that directory.
00:44 Then to ruby-tutorial.
00:47 Create a directory named oop-methods and cd into it.
00:54 What are Instance methods?
00:56 Instance methods are those methods that are available to all instances of the class.
01:03 Earlier we had studied how to create objects or instances of a class.
01:09 Create a new file in gedit as shown in the basic level Ruby tutorials.
01:14 Name it instance_methods.rb.
01:19 I have a working example of implementing instance methods.
01:24 You can pause the tutorial and type the code as we go through it.
01:29 I have defined a class named Product in this example.
01:33 I have called an initialize method to initialize the instance variables, "name" and "price".
01:41 I have also defined instance methods named "name" and "price".
01:47 Each of them return instance variables "name" and "price" respectively.
01:54 Instance methods are defined just like normal methods.
01:58 Earlier we had studied how to create methods in Ruby.
02:02 Shortly, we will see how these methods will be available to all instances.
02:07 Now, let us implement the logic we have.
02:11 Here, I have initialized a Product object and named it as "product_object_1".
02:18 I have initialized it with a name value and a price value.
02:24 The initializer block passes the values to the instance variables "@name" and "@price".
02:31 Now, this product instance or object can use the instance methods name and price.
02:37 On invoking these methods, we get the values stored in the instance variables.
02:43 Now, let us execute this code.
02:46 Switch to the terminal and type: ruby instance_methods.rb and press Enter to see the output.
02:56 You will see that it will print the values you initialized the object with.
03:02 Namely, "laptop" and "35,000".
03:07 Next, initialize another instance or object.
03:12 Let us name this object product_object_2.
03:18 This time, let us give a different set of values for name and price.
03:23 Now, let us call the instance methods- "name" and "price" for this object.
03:35 Next, let us switch back to the terminal and execute the code like before.
03:41 You will notice that it executes successfully and it prints out the new values.
03:48 This proves that instance methods are available to all objects of the class Product.
03:55 You should now be able to write your own instance methods.
03:59 Next, let us look at what class methods are.
04:04 Class methods are methods available only to the class.
04:09 These methods are not available to instances of the class.
04:14 There are different ways you can define class methods.
04:16 Let us look at an example.
04:18 Create a new file in gedit as shown in the basic level Ruby tutorials.
04:24 Name it class_methods.rb.
04:28 I have a working example of class methods.
04:32 You can pause the tutorial and type the code as we go through it.
04:36 I have defined a Product class like before.
04:40 I have also called an initializer, like before.
04:44 However, this time I have added an extra argument called description.
04:48 I am also using class variables to hold the values, unlike instance variables earlier.
04:55 This class will demonstrate to you the 3 different ways one can define class methods.
05:01 Checkout the class method declaration for name.
05:06 Here, it is defined using the class name "Product".
05:10 Then, checkout the second class methods declaration.
05:14 Here I have used the "self" keyword.
05:18 Next, checkout the third way you can define class methods.
05:23 Now let us implement these class methods.
05:27 Let us first initialize an object of Product, like before.
05:32 This time we are also giving a value for the description.
05:37 Now, let us invoke the class methods as shown here.
05:42 Now, let us execute the code and inspect the output.
05:47 Switch to the terminal and execute the code like before.
05:54 You will notice that it will print the values for name, price and description.
05:59 Now, you should be able to write your own class methods.
06:03 Next we shall see what accessor methods are.
06:07 Ruby uses accessor methods to access data, defined within classes.
06:13 Accessor methods comprise of setter methods and getter methods.
06:18 Setter methods set the values.
06:22 Getter methods get those values.
06:24 Ruby uses the word attr_accessor to declare these methods.
06:31 Let us look at an example of accessor methods.
06:35 Create a new file in gedit as shown in the basic level Ruby tutorials.
06:39 Name it accessor_methods.rb
06:43 I have a working example of implementing accessor methods.
06:47 You can pause the tutorial and type the code as we go through it.
06:52 I have defined a class named Product, in this example.
06:56 I have declared attr_accessor for 'name' and 'price'.
07:01 That is all that is required to use these types of methods.
07:05 Now let us put it to action.
07:07 I have initialized a Product object.
07:10 Then, I have set the name and price of the product object.
07:14 This is possible because the attr_declaration, by default, creates methods for setting values.
07:22 I have then attempted to print the values using the getter methods for 'name' and 'price'.
07:28 These getter methods were also generated by the declaration of attr_accessor.
07:35 Now let us execute the code like before.
07:40 You will notice that it prints the values that were set.
07:44 By now, you should be able to write your own accessor methods.
07:50 One thing to note is that accessor methods are, by default, instance methods.
07:55 Thus they can be accessed by different instances of the class Product.
08:00 In this tutorial, we have learnt about: instance methods, class methods and accessor methods.
08:06 As an assignment: define a class named Temperature.
08:10 Write an instance method using Ruby's accessor method syntax.
08:15 This method should calculate the Celsius for the given Fahrenheit.
08:20 Watch the video available at the following link.
08:23 It summarizes the Spoken Tutorial project.
08:26 If you do not have good bandwidth, you can download and watch it.
08:30 The Spoken Tutorial project team:
08:31 * Conducts workshops using spoken tutorials.
08:34 * Gives certificates to those who pass an online test.
08:38 For more details, please write to:

contact at spoken hyphen tutorial dot org.

08:44 Spoken Tutorial project is a part of the Talk to a Teacher project.
08:48 It is supported by the National Mission on Education through ICT, MHRD, Government of India.
08:55 More information on this mission is available at:

spoken hyphen tutorial dot org slash NMEICT hyphen Intro.

09:03 This is Anjana Nair, signing off. Thank you.

Contributors and Content Editors

Jyotisolanki, Pratik kamble