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Introduction to Ruby
Łukasz Wróbel
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About me
● Architect, team leader;
● high-traffic websites:
○ nk.pl;
○ Gadu-Gadu.
● “Memoirs of a Software Team Leader”;
● @lukaszwrobel
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Agenda
Ain't nobody got time for that!
Pure essence.
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Computers are like guys
Do this, then do that.
Be precise.
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Say hello!
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puts "Hello, world!"
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Variables
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message = "Hello world!"
puts message
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Calculations
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puts 5 + 3 * 2
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puts 5 + 3 * 2 # => 16?
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puts "H" + "ello"
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Conditions
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age = 22
if age > 30
puts "Too old"
else
puts "Acceptable"
end
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Repetitions
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puts "Hello, John"
puts "Hello, Mary"
puts "Hello, everyone"
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Functions to the rescue!
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def say_hello(name)
puts "Hello, " + name
end
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say_hello("John")
say_hello("Mary")
say_hello("everyone")
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say_hello("John")
say_hello("Mary")
say_hello("everyone")
# => "Hello, John"
# => "Hello, Mary"
# => "Hello, everyone"
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Introducing changes
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def say_hello(name)
puts "Hello, " + name + "!"
end
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Collections
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names = ["John", "Mary", "everyone"]
names.each do |name|
say_hello(name)
end
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Plus a few nice features
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prices = [100, 9.99, 14]
prices.reduce(:+)
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prices = [100, 9.99, 14]
prices.reduce(:+) # => 123.99
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Filtering
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[9, 5, 3, 4, 7].find_all
{|number| number > 5}
# => [9, 7]
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Mapping
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["These", "are", "words"].map
{|word| word.upcase}
# => ["THESE", "ARE", "WORDS"]
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Hashes
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friend = {
"name" => "William",
"age" => 45,
}
puts friend["name"]
# => "William"
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Symbols
Unique.
More common.
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friend = {
:name => "William",
:age => 45,
}
puts friend[:name]
# => "William"
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Classes
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class Person
def say_hello(name)
puts "My name is " + name
end
end
somebody = Person.new
somebody.say_hello("Emily")
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somebody = Person.new
somebody.say_hello("Emily")
somebody.say_hello("Somebody else")
somebody.say_hello("Whatever")
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Not only methods,
but also data
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class Person
def initialize(name)
@name = name
end
def say_hello
puts "My name is " + @name
end
end
me = Person.new("Łukasz")
me.say_hello # => "My name is Łukasz"
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It’s just the beginning.
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Thank you!
@lukaszwrobel