negamorgan

Morgan Evans

GitHub: NegaMorgan

BlogURL: http://negamorgan.github.io

Tagline: "Keep calm and clear cache."

Treehouse: http://teamtreehouse.com/NegaMorgan

negamorgan

require 'json'
require 'rest-client'

r = JSON.parse(RestClient.get('http://reddit.com/.json'))
p = r["data"]["children"]
posts_array = p.collect { |post| post["data"] }

# posts_array is an array of post hashes
# you can iterate over posts_array or do posts_array[0]["url"]

negamorgan

#New Ruby project set-up checklist

Add a simple README file

touch README.md

mkdir

• bin
• lib/models
• lib/views

negamorgan

# Euler problem 3
# used my old prime method from school week 1

class LargestPrime
  def largest(number)
    Math.sqrt(number).to_i.downto(2) do |i|
      # prime factor is a prime number that divides the integer exactly
      return i if number % i == 0 && prime?(i)
    end
  end

negamorgan

def solution(digits)
  group_by_five(digits).max
end
def group_by_five(digits)
  digits.split("")[0..-5].map.with_index do |digit, i|
    "#{digit}#{digits[i+1]}#{digits[i+2]}#{digits[i+3]}#{digits[i+4]}"
  end
end

negamorgan

def largest_product(digits)
  product_of_five(digits).max
end
def product_of_five(digits)
  digit_array = digits.to_s.split("")
  digit_array[0..-5].map.with_index do |digit, i|
    digit.to_i * digit_array[i+1].to_i * digit_array[i+2].to_i * digit_array[i+3].to_i * digit_array[i+4].to_i
  end
end

negamorgan

def fizzbuzz(n)
  1.upto(n).map do |num|
    response = ""
    response << "Fizz" if num % 3 == 0 
    response << "Buzz" if num % 5 == 0
    response.empty? ? num : response
  end
end

negamorgan

1.upto(999).select do |n| 
  n % 3 == 0 || n % 5 == 0
end.reduce(:+)

negamorgan

def even_fibonacci_numbers
  fibonacci_numbers.select {|n| n.even? }.reduce(:+)
end

def fibonacci_numbers
  numbers = [1, 2]
  while numbers[-1] < 4_000_000 do
    numbers << numbers[-2] + numbers[-1]
  end
  numbers[0..-2]

negamorgan

Studying for a Tech Interview Sucks, so Here's a Cheat Sheet to Help

This list is meant to be a both a quick guide and reference for further research into these topics. It's basically a summary of that comp sci course you never took or forgot about, so there's no way it can cover everything in depth. It also will be available as a gist on Github for everyone to edit and add to.

Data Structure Basics

###Array ####Definition:

• Stores data elements based on an sequential, most commonly 0 based, index.
• Based on tuples from set theory.