godfat

00:58 /p/tmp> jruby bm.rb
Rehearsal ------------------------------------------------
inject(fold)   2.898000   0.000000   2.898000 (  2.821000)
Hash+map       2.412000   0.000000   2.412000 (  2.412000)
--------------------------------------- total: 5.310000sec

                   user     system      total        real
inject(fold)   2.477000   0.000000   2.477000 (  2.477000)
Hash+map       2.292000   0.000000   2.292000 (  2.292000)

jcasimir

Friendly URLs

By default, Rails applications build URLs based on the primary key -- the id column from the database. Imagine we have a Person model and associated controller. We have a person record for Bob Martin that has id number 6. The URL for his show page would be:

/people/6

But, for aesthetic or SEO purposes, we want Bob's name in the URL. The last segment, the 6 here, is called the "slug". Let's look at a few ways to implement better slugs.

sumskyi

GeoEntity.last

SELECT geo_entities.* FROM geo_entities ORDER BY geo_entities.id DESC LIMIT 1

returns:

County id: 4, eid: nil, pid: nil, ename: nil, etype: 2, created_at: "2011-11-21 06:26:37", updated_at: "2011-11-21 06:26:37"

scottwb

# Add these methods to your ApplicationController. Then, any controller
# that inherits from it will have these methods and can programmatically
# determine what filters it has set.
class ApplicationController < ActionController::Base

  def self.filters(kind = nil)
    all_filters = _process_action_callbacks
    all_filters = all_filters.select{|f| f.kind == kind} if kind
    all_filters.map(&:filter)
  end

henrik

tmux cheatsheet

As configured in my dotfiles.

start new:

tmux

start new with session name:

kinopyo

Check whether a Paperclip attachment exists

Don’t simply test for the presence of the magic Paperclip attribute, it will return a paperclip Attachment object and thus always be true:

- if user.photo.present? # always true
  = image_tag(user.photo.url)

Kerrick

def fizz_buzz_1(max)
  arr = []
  (1..max).each do |n|
    if ((n % 3 == 0) && (n % 5 == 0))
      arr << "FizzBuzz"
    elsif (n % 3 == 0)
      arr << "Fizz"
    elsif (n % 5 == 0)
      arr << "Buzz"
    else

jboner

Latency Comparison Numbers (~2012)
----------------------------------
L1 cache reference                           0.5 ns
Branch mispredict                            5   ns
L2 cache reference                           7   ns                      14x L1 cache
Mutex lock/unlock                           25   ns
Main memory reference                      100   ns                      20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy             3,000   ns        3 us
Send 1K bytes over 1 Gbps network       10,000   ns       10 us
Read 4K randomly from SSD*             150,000   ns      150 us          ~1GB/sec SSD

gogojimmy

#!/usr/bin/env bash

# Pre-requisites
sudo apt-get -y update
sudo apt-get --no-install-recommends -y install build-essential openssl libreadline6 libreadline6-dev curl git-core zlib1g zlib1g-dev libssl-dev libyaml-dev libsqlite3-dev sqlite3 libxml2-dev libxslt-dev autoconf libc6-dev libgdbm-dev ncurses-dev automake libtool bison subversion pkg-config libffi-dev vim

# Download and compile Ruby 2.0.0-p0
cd /tmp
wget ftp://ftp.ruby-lang.org/pub/ruby/2.0/ruby-2.0.0-p0.tar.gz
tar -xvzf ruby-2.0.0-p0.tar.gz

epicserve

#!/usr/bin/env bash

# This script prints out all of your Redis keys and their size in a human readable format
# Copyright 2013 Brent O'Connor
# License: http://www.apache.org/licenses/LICENSE-2.0

human_size() {
        awk -v sum="$1" ' BEGIN {hum[1024^3]="Gb"; hum[1024^2]="Mb"; hum[1024]="Kb"; for (x=1024^3; x>=1024; x/=1024) { if (sum>=x) { printf "%.2f %s\n",sum/x,hum[x]; break; } } if (sum<1024) print "1kb"; } '
}