Ruby lesson 4. I will focus on Getting Control Statements (IF statement, Case Expressions, loops), Comments, and File Control. It can provide extensive knowledge.
A control statement is a statement that determines whether other statements are active. If a statement decides whether another statement should be executed, or one of the two statements to be executed. A loop determines the number of times another expression should be executed.
Basically have 3 control statement
IF Statement in Ruby
If a statement is used to check the condition, it can be a condition or more. The special feature of it is that you can check any gap. The following example will make it clear to you.
ismale = false if ismale puts "you are male" else puts "you are not male" end
This Code output is you are not male.
The Case Expressions is used to check several non-gap conditions. This works very fast and gets the idea below
def get_day_name(day) day_name=" " case day when "mon" day_name = "Monday" when "tue" day_name = "Tuesday" when "wed" day_name = "Wednesday" when "tur" day_name = "Thursday" when "fri" day_name = "Friday" when "sat" day_name = "Saturday" when "sun" day_name = "Sunday" else day_name = "Invalid" end return day_name end puts get_day_name("wed")
This code output is Wednesday.
Loops have main 3 loops in php
- For loop
- While loop
Now I show the First 3 loops using Code. See Below all code output is the same. output is : 1,2,3,4,5,6,7,8,9,10.
For Loop with Arry
num = [1,2,3,4,5,6,7,8,9,10] for num in num puts num end
index = 1 while index < 8 puts index index + = 1 end
Comments are a special character in programming.
# single line comment = multiline comment =
File Control using Ruby
Here we show you how to handle files without opening them. see below
file.open("test.txt",r) do |tile| puts file.read end
File.open("employee.txt","a") do |file| file.write ("sanka") end
File.open ("index.html","w") do |file| file.write("<h1>Hello</h1>") end
Read and Write
File.open ("employee.txt","rt") do |file| file.readline() file.write ("overridden") end
Class & Object
Class is collection of objects and functions. In computer programming, a function object is a construct that allows an object with the same syntax to be called or called a normal function. Active objects are often referred to as funksters.
This is the mining of the object and class. now we can try to add it ruby. look below example.
class Book attr_accessor :title, :author, :pages end book1 = Book.new() book1.title = "Harry Potter" book1.auther = "JK" book1.pages = 400 puts book1.pages
Output is 4000.
See the below example. that use code reuses it easy for developing softwares.
Class attr_accessor:name, :major, :gpa def initialize (name,major,gpa) @ name = name @ major = major @ gpa = gpa end end student1 = student.new ("harry","bio","3.6") student2 = student.new ("jhone","chem","2.1") puts.student1.name
Output is harried.
Create a Ruby 2D Game
First, install ruby 2d gem. open cmd
gem install ruby2d
Click Here to get the Source code.
you can see the below output in-game.
Thank you for all!
See you Next Lesson Soon!