Ruby - Strings
"a string"
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'a string'
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“Concate” + “nation”
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“#{concate}#{nation}”
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astring.length
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astring.empty?
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"a,b,c".split(',')
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Result: [a,b,c] |
Single quotes string, auto escape characters.
Ruby - Array
foo = [a,b,c,d]
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Used for all examples below |
foo[n]
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foo.first, foo.second
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foo.length
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foo.last == foo[-1]
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foo.empty?
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foo.include?(x)
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foo.sort[!]
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foo.shuffle[!]
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foo.reverse[!]
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foo.push(x) or foo << x
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foo.join(",")
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Result: "a, b, c, d" |
foo[0..2]
|
Result: [a,b,c] |
foo[1..-1]
|
Result: [b,c,d] |
('a'..'d').to_a == foo
|
Ruby - Block
3.times { puts "foo" }
|
Inline Block |
(1..5).each do |i|
puts 2 * i
end
|
Multi Line Block |
%w[A B C].map { |char| char.downcase }
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%w[A B C].map(&:downcase)
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The last 2 lines result in an array of ["a", "b", "c"]. The %w creates an array of string. The last one is a weird Ruby shortcut.
|
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Ruby - Conditionals
puts "string is not empty" if !astring.empty?
puts "string is not empty" unless astring.empty?
if <expression>
...
else
...
end if
|
Ruby - Hash + Symbol
foo = { "name" => "John", "id" => "JH" }
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foo["name"]
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"John" |
foo = { name: "John", id: "JH" }
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foo[:id]
|
"JH" |
foo.each do |key, value|
puts "#{key.inspect} - #{value.inspect}"
end
|
:name - "John"
:id - "JH" |
|
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Ruby - Objects
anobject.nil?
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True or False |
anobject.to_s
|
To String |
Ruby - Class
module BunchOfMethods
def moduleMethod1
...
end
def moduleMethod2
...
end
end
class MyClass < MySuperClass
attr_accessor :attributeA, :attributeB
def initialize(attributes = {})
@attributeA = attributes[:attributeA]
@attributeB = attributes[:attributeB]
end
def NiceString
"#{@attributeA} #{@attributeA}"
end
end
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