Joshva JoshvaR88

What's a Symbol and why is it imporant?

In Ruby, a Symbol is the most efficient way, in terms of time and memory, to represent a set of characters.

What does a Symbol look like?

Most commonly, a Symbol is a single word prefixed by a colon:

:hello

What's a Hash and why is it important?

A Hash is a collection of key-value pairs. To add, fetch, modify, and delete a value from a Hash, you refer to it with a unique key.

While an Array is indexed by Integers only, a Hash is keyed by any object -- Strings, Integers, etc.

In other programming languages, a Hash might be known as an 'associative array', 'dictionary', or 'HashMap'.

What does a Hash look like?

2015-01-29 Unofficial Relay FAQ

Compilation of questions and answers about Relay from React.js Conf.

Disclaimer: I work on Relay at Facebook. Relay is a complex system on which we're iterating aggressively. I'll do my best here to provide accurate, useful answers, but the details are subject to change. I may also be wrong. Feedback and additional questions are welcome.

What is Relay?

Relay is a new framework from Facebook that provides data-fetching functionality for React applications. It was announced at React.js Conf (January 2015).

	class CustomSearch < Spree::Core::Search::Base

	protected
	def add_search_scopes(base_scope)
	statement = nil
	search.each do \|property_name, property_values\|
	property = Spree::Property.find_by_name(property_name.gsub("_any", ""))
	next unless property

	substatement = product_property[:property_id].eq(property.id).and(product_property[:value].eq(property_values.first))

	def ProductFilters.option_with_values(option_scope, option, values)
	# get values IDs for Option with name {@option} and value-names in {@values} for use in SQL below
	option_values = Spree::OptionValue.where(:presentation => [values].flatten).joins(:option_type).where(OptionType.table_name => {:name => option}).pluck("#{OptionValue.table_name}.id")
	return option_scope if option_values.empty?

	option_scope = option_scope.where("#{Product.table_name}.id in (select product_id from #{Variant.table_name} v left join spree_option_values_variants ov on ov.variant_id = v.id where ov.option_value_id in (?))", option_values)
	option_scope
	end

	# option scope

	<html>
	<head>

	<title>Google Maps Multiple Markers</title>
	<script src="http://maps.google.com/maps/api/js?sensor=false" type="text/javascript"></script>
	</head>
	<body>
	<div id="map" style="height: 400px; width: 500px;">
	</div>
	<script type="text/javascript">

	class Car
	attr_reader :mileage, :service
	def initialize(mileage = 0, service = 3000)
	@mileage, @service = mileage, service
	@observers = [Notifier.new]
	end
	def log(miles)
	@mileage += miles
	notify_observers(self, miles)
	end

	# install openjdk
	sudo apt-get install openjdk-7-jdk

	# download android sdk
	wget http://dl.google.com/android/android-sdk_r24.2-linux.tgz

	tar -xvf android-sdk_r24.2-linux.tgz
	cd android-sdk-linux/tools

	# install all sdk packages

	Disclaimer: The instructions are the collective efforts from a few places online.
	Nothing here is my original. But I want to put them together in one place to save people from spending the same time as I did.

	First off, bundle.
	==================

	1. cd to the project directory
	2. Start the react-native packager if not started
	3. Download the bundle to the asset folder:
	curl "http://localhost:8081/index.android.bundle?platform=android" -o "android/app/src/main/assets/index.android.bundle"

	# Sample implementation of quicksort and mergesort in ruby
	# Both algorithm sort in O(n * lg(n)) time
	# Quicksort works inplace, where mergesort works in a new array

	def quicksort(array, from=0, to=nil)
	if to == nil
	# Sort the whole array, by default
	to = array.count - 1
	end