define a array

x=[]
x << "Apple"
x << "orange"
x << "banana"
puts x.length
puts x[0]
puts x[1]
puts x[2]
puts x.pop
puts x.pop
puts x.length

iteration string

string1="this is a ruby"
string1.scan(/./) {|letter| puts letter}
string1.scan(/../) {|letter| puts letter}

string2="there are $1000 dollers here 10 days"
string2.scan(/\d+/) do |x|
puts x
end

string substitution

string1="the language name is ruby"
puts string1.sub('a','A')
puts string1.gsub('a','A')

interpolation string

x=10
y=20
puts "#{x}+#{y}=#{x+y}"

my_string="It\'s a #{"bad " *5} world"
puts my_string

character char and value

avalue=?a
puts avalue
puts avalue.chr

mutli line in ruby string

string1="<<"NEF
welcome to use ruby language
nice to meet you
NEF

puts string1

string2=%q{
welcome to use ruby language
nice to meet you
}

puts string2

string3=%q!
welcome to use ruby language
nice to meet you
!

puts string3

loop syntax

syntax 1:

4.times {
puts "welcome to use ruby language"
}

syntax 2:

1.upto(5){
puts "nice to meet you"
}

10.downto(5){
puts "nice to meet you"
}

0.step(50,5){
puts "welcome to use ruby language"
}

1.upto(5) do |number|
puts number
end

if-else syntax

age=15
color="blue"
if age > 10 && age <25
puts "you are very young"
else
puts "you are not young"
end


if color=="blue" || color!="red"
puts "cold color"
else
puts "warm color"
end

class string method

string1="Test"

puts string1.upcase
puts string1.downcase
puts string1.capitalize
puts string1.reverse
puts string1.chop
puts string1.swapcase
puts string1.hash
puts string1.sum
puts string1.next
puts string1.class
puts string1.length
puts string1.slice(2,2)

define a function

class Cat
attr_accessor:name, :size
def bark
puts "bark!!!"
end
end

cat1=Cat.new
cat1.name="putty"
cat1.size=20
puts cat1.name
puts cat1.size
cat1.bark

define a class inherit another class

class Person
attr_accessor:name, :age, :email
end

class Cat < Person
attr_accessor:eye
end

pson1=Person.new
pson1.name="Tommy"
pson1.age=22
pson1.email="tommy@gmail.com"

cat1=Cat.new
cat1.name="putty"
cat1.age=5
cat1.eye="black"

puts cat1.name
puts cat1.age
puts cat1.eye

Define a class

class Person
attr_accessor:name, :age, :email
end

pson1=Person.new
pson1.name="Tommy"
pson1.age=22
pson1.email="tommy@gmail.com"

puts pson1.name
puts pson1.age
puts pson1.email