I am working on a fastlane file and it contains Ruby code, I want to optimise the code and functions used in that file so thought why not learn some basics of Ruby programming language, here is what I learned
- Ruby is Object oriented programming language, good news for you Kotlin, Java, Swift devs
- Ruby development focus was on programmer and not the machine so the developer wanted it to be fun and easy to use, will see about that in a while.
- All Ruby code is run using an interpreter, but there are some implementation of Ruby where we can compile the code and run on VMs.
- Most famous Ruby interpreter is called MRI (Matz's Ruby Interpreter)
- Ruby has a Garbage collector
- Ruby became most popular due to the Ruby on Rails web application development framework. which is being used by large companies like, Github, twitch, Hulu, etc.
This would be the file name of a ruby app.
App.rb
To run the ruby file simply go to terminal and enter this command
ruby your_file_name.rb
(If Ruby is not installed in the system first install that, would be much simpler to use something like brew on a mac)
Here we print a simple "Hello World!"
#Printing
puts "Hello"
print "World"
puts "!"
puts simply prints and enter a new line as well, whereas print will only print in the same line.
- variable names are case sensitive, standard is start with a lower case word, additional word separated by
_ ex. this_is_variable
name = "Honey" # String
age = 30 # Integer
temp = 24.5 # Decimal
is_coding = true # Boolean
name = "Div"
puts "Your name is #{name}"
# or
puts "Your name is " + name
casting of data types
puts 3.14.to_i # To Integer
puts 3.to_f. # To FLoat
puts 3.0.to_s # To String
puts 100 + "50".to_i # To Integer and add a number
puts 100 + "50.99".to_f # To FLoat and add to a number
How to play with String
greeting = "Hello"
#indexes: 01234
puts greeting.length
puts greeting[0]
puts greeting.include? "llo"
puts greeting.include? "z"
puts greeting[1,3] #ell
how to play with numbers
puts 2 * 3 # Basic Arithmatic: +,-,/,*
puts 2 ** 3 # Exponent
puts 10 % 3 # Module Op, : returns remainder of 10/3
puts 1 + 2 * 3 # order of operations
puts 10 / 3.0 # int's and doubles
num = 10
num += 100 # +=, -=, /= , *=
puts num # 110
num -36.8
puts num.abs()
puts num.round()
# usefull Math class API
puts Math.sqrt(144)
puts Math.log(0)
Getting user inputs ?
puts "Enter your name: "
name = gets # better to use gets.chomp , which will not take the new line when press enter
puts "Hello #{name}, how are you ?"
# Example 2
puts "Enter first num:"
num_one = gets.chomp
puts "Enter second num:"
num_two = gets.chomp
puts num_one.to_f + num_two.to_f
gets wait for a user input in the terminal, gets.chomp only takes and string entered and ignores the new line when enter is pressed after input.
Arrays in Ruby
numbers = [4, 8, "wow", 16, 34]
# can have multiple data types in an array
numbers[0] = 90
puts numbers[0] # prints 90
puts numbers[1] # prints 8
puts numbers[-1] # prints 34, as last number from array
puts numbers[2,3] # first is the index argument, second the range, so prints wow,16,34
puts numbers[2..4] # prints the range from 2 to 4 as wow,16,34
puts numbers.length # prints the length of array
# Array methods
friends = []
friends.push("Oscar")
friends.push("Kevin")
friends.push("Taras")
friends.pop # would pop the last element from the array
friends.reverse # reverse the elements in the array
friends.sort # sorts the array , would not work with multiple data types in an array, will sort but with wierd results
friends.include? "kevin" # will return if string exists or not in array
Functions or Methods
def add_numbers(num1,num2=99)
return num1 + num2
end
# we define the function with a def keyword, followed by name, and params, we can set param value as default, to close the function scope we need to set an end
sum = add_number(4)
puts sum # prints 4 + 99 = 103
Conditionals
is_student = false
is_smart = true
if is_student and is_smart
puts "You are a student"
elseif is_student and !is_smart
puts "You are not a smart student"
else
puts "You are not a student"
end
# >,<, >= , <=, !=, == , String.equals()
if 1 > 3
puts "number comparission was true"
end
if "a" > "b"
puts "string comparison was true"
end
Switch Statements
my_grade = "A"
case my_gradde
when "A"
puts "You pass"
when "F"
puts "You fail"
else
puts "Invalid Grade"
end
Dictionaries or Associated Arrays, can store key value pairs
- Dictionaries do not have a indexing, so numbers will be part of the keys
# Keys has to be Unique
test_grades = {
"Andy" => "B+",
:Stanley => "C", # can also define in this format if do not want to use the stirng quotes
"Ryan" => "A",
3 => 95.2,
}
test_grades["Andy"] = "B-"
puts test_grades["Andy"]
puts test_grades[:Stanley]
puts test_grades[3]
While and For loops
# While loop
index = 1
while index <= 5
puts index
index += 1
end
# For loop
for index in 0..5
puts index
end
5.times do |index|
puts index
end
numbers = [4,5,6,3,4,6]
for num in numbers
puts num
end
numbers.each do |num|
puts num
end
Exception catching in Ruby
num = 10/0
begin
num = 10/0
rescue # will catch any error
puts "Error"
end
# specific error catching
begin
num = 10/0
rescue ZeroDivisionError
puts "Error"
rescue
puts "All other error"
end
raise "Made up exception"
OOPs in Ruby
- Everything in Ruby is an object, similar to JS
attr_accessor will define the attributes for the class- can simple add functions inside the class
- also
self would be like this will be in the scope of the class object
class Book
attr_accessor :title, :author
def readBook()
puts "Reading #{self.title} by #{self.author}"
end
end
book1 = Book.new()
book1. title = "Harry Potter"
book1.author = "JK Rowling"
book1.readBook()
puts book1.title
constructors in ruby classes
class Book
attr_accessor :title :author
def initialize(title, author)
@title = title
@author = author
end
def readBook()
puts "Reading #{self.title} by #{@author}"
end
end
book1 = Book.new("Harry Potter", "JK Rowling")
# book1.title = "some new title"
Getters and Setters
class Book
attr_accessor :title :author
def initialize(title, author)
self.title = title
@author = author
end
def title=(title)
puts "Set"
@title = title
def title
puts "Get"
return @title
def readBook()
puts "Reading #{self.title} by #{@author}"
end
end
book1 = Book.new("Harry Potter", "JK Rowling")
# book1.title = "some new title"
Inheritance
class Chef
def make_chicken()
puts "Making chicken"
end
def make_salad()
puts "Making Salad"
end
end
class ItalianChef < Chef # using this < sign makes the inheritance possible
def make_pasta()
puts "Making Pasta"
end
end
chef = Chef.new()
chef.make_chicken()
italian_chef = ItalianChef.new()
italian_chef.make_chicken()
italian_chef.make_pasta()
How to Import ruby files ?
here in the example, it will look into a folder named test for a file named file_name.rb to import.
require_relative "test/file_name"
I had so much fun learning this language, and going to clean my fastfiles which have now 500+ lines of duplicated code, the OOP concepts will help me clean it and make better automations to deploy our mobile apps.
Thanks for reading 🙏