mkreyman

# Given a multidimensional list of characters, print out a spiral traversal of the lists.
#
# iex(1)> matrix = [~w(A B C D), ~w(E F G H), ~w(I J K L), ~w(M N O P)]
# [
#   ["A", "B", "C", "D"],
#   ["E", "F", "G", "H"],
#   ["I", "J", "K", "L"],
#   ["M", "N", "O", "P"]
# ]
# iex(2)> Spiral.traverse(matrix, [])

mkreyman

defmodule Util.PipeDebug do

  @moduledoc """
  Support the injection of inspect capabilities in an elixir pipe |> pipestream.
  """

  defmacro __using__(_opts) do
    quote do
      import Util.PipeDebug, warn: false
    end

mkreyman

...
def with_locale(request)
  query = URI.parse(request.original_fullpath).query
  return '' unless query
  query_params = query.split('?').inject({}) { |h, q| k, v = q.split('='); h[k] = v; h }
  locale = query_params['locale']
  locale ? "?locale=#{locale}" : ''
end

Rails.application.routes.draw do

mkreyman

module Enumerable
  def to_histogram
    inject(Hash.new(0)) { |h, x| h[x] += 1; h}
  end
end

class Bag
  def initialize
    @bag_of_objects = []
  end

mkreyman

# app/models/user.rb with custom uniqueness validation errors

class User < ActiveRecord::Base
...

  def create_or_update
    super
  rescue ActiveRecord::RecordNotUnique => e
    case e.message
    when /index_users_on_login/

mkreyman

class AddUniquenessConstraintToUsersGuid < ActiveRecord::Migration
  def up
    # Delete all but the first user for users with duplicate :guid
    duplicate_guids = User.select(:guid).group(:guid).having('count(*) > 1').pluck(:guid)
    duplicate_guids.each do |duplicate_guid|
      next unless duplicate_guid.present?
      users_to_be_deleted = User.where(guid: duplicate_guid).order('id ASC')[1..-1]
      users_to_be_deleted.each(&:destroy)
    end

mkreyman

#  1.  This is a numbered list of twelve statements.
#  2.  Exactly 3 of the last 6 statements are true.
#  3.  Exactly 2 of the even-numbered statements are true.
#  4.  If statement 5 is true, then statements 6 and 7 are both true.
#  5.  The 3 preceding statements are all false.
#  6.  Exactly 4 of the odd-numbered statements are true.
#  7.  Either statement 2 or 3 is true, but not both.
#  8.  If statement 7 is true, then 5 and 6 are both true.
#  9.  Exactly 3 of the first 6 statements are true.
#  10. The next two statements are both true.

mkreyman

module Enumerable
  def to_histogram
    inject(Hash.new(0)) { |h, x| h[x] += 1; h}
  end
end

class Bag
  def initialize
    @bag_of_objects = []
  end

mkreyman

# spec/spec_helper.rb

def permutations(num)
  [true, false].repeated_permutation(num)
end

# spec/models/welcome_email_logic_spec.rb
require 'spec_helper'

describe WelcomeEmail do

mkreyman

module Enumerable
  def to_histogram
    inject(Hash.new(0)) { |h, x| h[x] += 1; h}
  end
end

p [1, 2, 2, 2, 3, 3].to_histogram
# => {1=>1, 2=>3, 3=>2}

p ["a", "b", nil, "c", "b", nil, "a"].to_histogram