havenwood

# Determines how many cpus the virtual machine should be given. Uses half of
# what's available on the host with a default of 4.
def numvcpus
  begin
    os_cpu_cores / 2
  rescue
    4
  end
end

havenwood

#!/bin/sh

gem search --no-vers | parallel -j0 -I$ 'curl -O `curl https://rubygems.org/api/v1/gems/$.json | jq -r .gem_uri`'

havenwood

class Weazel
  CHARS = [*'A'..'Z', ' ']

  def initialize target
    @target = target
    @best = Array.new(28) { CHARS.sample }.join
  end

  def call
    0.upto Float::INFINITY do |n|

havenwood

class Integer
  def collatz_chain_size
    n = self
    chain = []
    until n == 1
      chain << n
      n.even? ? n /= 2 : n = n * 3 + 1
    end
    [chain.size, chain.first]
  end

havenwood

class MyClass
  attr_accessor :user, :type
  def initialize user: 'smith', type: 'pleb'
    @user = user
    @type = type
  end
end
 
both = MyClass.new user: 'blah', type: 'pleb'
just_one = MyClass.new type: 'pleb'

havenwood

str = "aaa [first_name] bar [first_name] [last_name]"
last = str.scan(/\[last_name\]/).size
first = str.scan(/\[first_name\]/).size
remaining = str.gsub(/\[(first_name|last_name)\]/, '').size
first * 15 + last * 10 + remaining

havenwood

require 'benchmark'

hash = {}

Benchmark.measure do
  1_000_000.times do
    hash = {}
  end
end.real
#=> 0.245904

havenwood

# An octothorp (#) starts a single-line comment.

=begin
   Starting with a =being and ending with a =end
   makes it a multi-line comment.
=end

##
# 1. Variables and flow control.
#

havenwood

def fib n
  a, b = 1, 2
  sum = 0
  while a < n
    sum += a if a.even?
    a, b = b, a + b
  end
  sum
end

havenwood

Ruby Number Conversion Chart

From	To	Expression