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Ruby Lecture 3

Programmer of the day: Kent Beck

FizzBuzz solutions on ?ruberque?

TDD: able to write the code that you wish you had

Array Review:

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empty[0] = "filled" #=> can assign slots one at a time
easy_as[1, 5] #=> can slice elements off, have elastic arrays --> can add elements to an array without doing anything else

Lecture:

Object orientation- we send object methods important to identify who the receiver is and what the method is part of dot notation: every method returns an object, so you can chain another method on it it’s the return of the previous method that is the receiver for the following method

the strip method is part of the family of normalization

gsub = global substitution sub will only replace the first occurrence it encounters

== is the same as eql method

methods that end with question marks –> the ? is part of the method name that indicates it returns a boolean value

strings like arrays can be sliced

match accepts a pattern of REGEX -the string literal for patterns are /a/e/i/o/u -check http://rubluar.com

Iteration is a fancy word for looping

anything that can iterated upon is described as an enumerable strings and arrays are enumerables

Scope

scope gates – every time you see a ‘do’, ‘end’, ‘def’ keyword your scope changed.

blocks have an exclusive scope. If it is defined in that block and only in that block it is accessible for the outside. method scopes are even stricter. cannot access method outside of that particular method. parameters are how you pass in values into a method.

2nd program- (8:25- 8:35) artist, album, song sorting

first step in a program is usually to set up state

More Data Types Hashes a lot like an array in that it is a collection object. An array is only indexed, so you can only refer to the objects within the array by its position

Literal Constructors:

”” - strings

/ - REGEX

[] - array

{} - hashes

: - symbols

Hashes are valuable when you care about the meta data

every time you create a new string, it creates a new object in memory a symbol is an immutable object

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vending machine {
  a: => ["snickers", "twix", "kit kat"]
}
puts vending_machine[:a][0] #=> this accesses the :a key and the 0th position of the array which is the value

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