Tag Archives: programming

Learning to Program on Your Own

Learning how to code is like learning anything else – You have to do it. The hardest part is figuring out where to begin, and then you need some mechanism to show you that you’re making progress. The latter is important because it motivates you to keep going.

First, have a goal. I initially wanted to make AOL “punters” (apps that kicked other users offline) and malware. I found them interesting. Do you want to program games? websites? Facebook Apps? Apps for OS X?

Once you have the goal, do research on how those apps are made, particularly on the language used, APIs/libraries used, and so on.

When starting, you will be learning a lot of concepts that you will see no use for. If-then statements, variables, etc. You might understand the basic idea of what a variable is, but might wonder – why would I ever use this instead of putting the value in directly? At this stage, it’s important that you remain persistant and just go through the examples/exercises in your book (or those provided by your tutor). I noticed that most people will struggle through the first set of concepts, and then lose interest and quit after seeing that they aren’t doing anything interesting. One day, you’ll be doing something and everything will fall into place. An A-Ha moment.

You’re learning a bunch of stuff that doesn’t really connect with each other. How does printing “Hello World” to the screen eventually become a 3D game? How do I go from a console app to a window app? How does knowing what a variable or constant is translate to a web development project?

It’s a plateau — and I want to stress that this applies to almost anything, not just programming. You begin by learning a lot of stuff, very slowly making progress, and over time you begin to see that you kinda “know” what’s happening behind the scenes of the apps you’re using. After that, learning because easier and quicker. Getting to that level requires persistance.

My Turning Point – Stop Asking “What Should I Code?”

When I first began coding, I had the mentality that I had to “learn how to program” before “making app X” – This is logical but the way I structured in my head was important in impeding my progress. I divided learning how to program and making app X into two separate goals. It was a problem because it migrated me away from the goal of “making app X.” I began asking the wrong question – what should I code to learn how to program?

Instead, I should have been asking – what should I learn next, to reach my goal of making app X? I broke down app X into individual tasks, and then began learning how to do each one. For example, let’s say my goal is to program a game.

If I ask “what should I code to learn how to program?” I will spend a lot of time learning things I might not need anytime soon (or ever), I will get nowhere near reaching my goal, and will become unmotivated and quit before getting there. Instead, I would break down the game into individual tasks (this requires research) and work on learning each one.

Let’s see, I need to figure out how to make a window/draw things on screen. That becomes my new short term goal. I dig deeper and learn that I need to learn the Windows API. I learn that the Windows API is how one draws to the screen. But the Windows API is another thing I need to learn, so that becomes the immediate short term goal. Digging deeper, I realize that the Windows API is just a bunch of functions with some conventions that I need to memorize.

Now my goal is somewhat clearer. I begin reading about the Windows API, making different small apps to make sure I understand what I’m reading. Eventually I am able to draw a window and controls. Great. I still don’t have a game. What’s next? I need to draw graphics. I dig into how it’s done and learn that the Windows API provides a set of functions graphics. I’m familiar with the Win API and so I just begin learning the graphics lib. I make a few dozen apps drawing basic circles, loading bitmap images, etc. Now my goal of making a game is starting to take shape in my head. I can mentally structure how the game will be, minus a few concepts I might not have learned yet.

Persistence.

Multiple Monitors vs One Big Screen

dualscreen
Most people I know who’ve never used dual screen ask me why I don’t invest in one big monitor instead. There’s a big difference between having multiple monitors and having just one, no matter the size. Though which is better really depends on what you’re using the computer for, what OS/window manager you’re using, and how you use your particular setup.

For programming, and the way I use my desktop (gnome+compiz), having multiple screens is much more productive than one big screen because I hate minimizing and dragging windows. If I’m coding in rails for example, I can have my editor maximized in one screen, and a reference window or a `tail -f file.log` maximized in the other screen. With a big monitor I would need to manually resize each window or depend on my window managers cascade feature, which requires some manual resizing as well.

For coding or writing, a killer setup would be having two or three widescreen displays setup vertically side-by-side. I noticed I only look at 3/4th of the screen real estate when I’m coding, and when I hack or write, Continue reading Multiple Monitors vs One Big Screen

Scraping Google Trends with Mechanize and Hpricot

This is a small Ruby script that fetches the 100 trends of the day for a specific date. If multiple dates are searched, one can find out how many times a keyword occurred between two dates, or just find out what keywords are constantly appearing on the top 100 list. The script is incomplete and one must implement the “implement me!” methods to get full functionality. This, in its current state, should serve as a good starting point for scraping Google Trends.

On a technical note, it’s using mechanize, hpricot, tempfile (for the cache). A lot of this is just copy & paste programming from the earlier anime scraper.

To grab the gems (rdoc takes 10x as long as the gem to fetch and install):

sudo gem install mechanize --no-rdoc
sudo gem install hpricot --no-rdoc
#!/usr/bin/env ruby
# biodegradablegeek.com
# public domain
#

require 'rubygems'
require 'hpricot'
require 'tempfile'
require 'mechanize'
#require 'highline/import'
#HighLine.track_eof = false

$mech = WWW::Mechanize.new
$mech.user_agent_alias = 'Mac Safari'
$master = []

def puts2(txt=''); puts "*** #{txt}"; end

class Cache
  def initialize
    # Setup physical cache location
    @path = 'cache'
    Dir.mkdir @path unless File.exists? @path

    # key/val = url/filename (of fetched data)
    @datafile = "#{@path}/cache.data"
    @cache = load @datafile
  end

  def put key, val
    tf = Tempfile.new('googletrends', @path)
    path = tf.path
    tf.close! # important!

    puts2 "Saving to cache (#{path})"
    open(path, 'w') { |f|
      f.write(val)
      @cache[key] = path
    }

    save @datafile
  end

  def get key
    return nil unless exists?(key) && File.exists?(@cache[key])
    open(@cache[key], 'r') { |f| f.read }
  end

  def files
    @cache.values
  end

  def first
    @cache.first
  end

  def exists? key
    @cache.has_key? key
  end

private
  # Load saved cache
  def load file
    return File.exists?(file) ? YAML.load(open(file).read) : {}
  end

  # Save cache
  def save path
    open(path, 'w') { |f|
      f.write @cache.to_yaml
    }
  end
end

$cache = Cache.new

def fetch(url)
  body = $mech.get(url).body()
  $cache.put(url, body)
  body
end

def getPage(url)
  body = $cache.get(url)

  if body.nil?
    puts "Not cached. Fetching from site..."
    body = fetch url
  end
  body
end

def loadState
  mf = 'cache/master.data'
  $master = File.exists?(mf) ? YAML.load(open(mf).read) : {}
  $master = {} if $master==false
end

def saveState
  open('cache/master.data', 'w+') { |f|
    f.write $master.to_yaml
  }
end

def main
  #loadState

  # Grab top 100 Google Trends (today)
  #date = Time.now.strftime '%Y-%m-%d'
  date = '2009-01-21'

  puts2 "Getting Google's top 100 search trends for #{date}"
  url = "http://www.google.com/trends/hottrends?sa=X&date=#{date}"
  puts2 url

  begin
    body = getPage(url)
  rescue WWW::Mechanize::ResponseCodeError
    puts2 "Couldn't fetch URL. Invalid date..?"
    exit 5
  end

  puts2 "Fetched page (#{body.size} bytes)"

  if body['There is no data on date']
    puts2 'No data available for this date.'
    puts2 'Date might be too old or too early for report, or just invalid'
    exit 3
  end

  doc = Hpricot(body)

  (doc/"td[@class='hotColumn']/table[@class='Z2_list']//tr").each do |tr|
    td = (tr/:td)
    num = td[0].inner_text.sub('.','').strip
    kw = td[1].inner_text
    url = (td[1]/:a).first[:href]
    Keyword.find_or_new(kw) << Occurance.new(num, date, url)
  end
  puts "Got info on #{$master.size} keywords for #{date}"
  puts "keyword '#{$master.first.name}' occured #{$master.first.occurances} times"
end

class Occurance
  attr_accessor :pos, :date, :url
  def initialize(pos, date, url)
    @pos = pos
    @date = date
    @url = url
  end
end

class Keyword
  attr_accessor :name, :occurances
  def initialize(name)
    @name = name
    @occurances = []
    @position_average = nil
    @count = nil
    $master << self
  end

  def self.find_or_new(name)
    x = $master.find { |m| name==m.name }
    x || Keyword.new(name)
  end

  def << occurance
    @occurances << occurance
  end

  def occured_on? datetime
    raise 'implement me'
  end

  def occured_between? datetime
    raise 'implement me'
  end

  def occurances datetime=nil
    raise 'implement me' if datetime
    @occurances.size
  end

  def occurances_between datetime
    raise 'implement me'
  end

  def pos_latest
    @occurances.last.date
  end

  def pos_average
    @position_average
  end

  def pos_average_between datetime
    raise 'implement me'
  end
end

#   Instance= [num, date, url]
#   Keyword=[Instance, Intance, Instance]
#   Methods for keywords:
#   KW.occured_on? date
#   KW.occured_between? d1, d2
#   KW.occurances
#   KW.occurances_between? d1, d2
#   KW.pos_latest
#   KW.pos_average
#   KW.pos_average_between

#   KW has been on the top 100 list KW.occurances.size times
#   The #1 keywords for the month of January: Master.sort_by KW.occurances_between? Jan1,Jan31.pos_average_between Jan1,Jan31
#
#   Top keywords: sort by KW.occurances.size = N keyword was listed the most.
#   Top keywords for date D: Master.sort_by KW.occured_on (x).num

main

Got API? Instantly Search API Documentation

gotAPI.com does an excellent job congregating API documentation for numerous programming languages under an AJAX interface. No more bulging neck veins or fulmination when you can’t remember the order of those pesky arguments.

No support for your favorite language? Contribute.

You can add a gotAPI Search Widget to your site: http://www.gotapi.com/widgets/index.html
See Ruby/Rails widget below (requires Javascript). Still in beta and might have UI issues, but it’s functional. Try typing map or validates and hitting enter.

Quick Ruby / Rails lookup

powered by gotAPI.com

GitHub Now Open to the Public

GitHub.com, the “easiest (and prettiest)” version control system, is now open to the public. It’s free for Open Source programs (albeit limited to 100MB of space).

If you’re not sure what git (or Revision Control) is, here are some resources:
Wikipedia on Revision Control

(excerpt) “Revision control (also known as version control (system) (VCS), source control or (source) code management (SCM)) is the management of multiple revisions of the same unit of information. It is most commonly used in engineering and software development to manage ongoing development of digital documents like application source code, art resources such as blueprints or electronic models, and other critical information that may be worked on by a team of people. Changes to these documents are usually identified by incrementing an associated number or letter code, termed the ‘revision number’, ‘revision level’, or simply “revision” and associated historically with the person making the change. A simple form of revision control, for example, has the initial issue of a drawing assigned the revision number ‘1’. When the first change is made, the revision number is incremented to ‘2’ and so on.”

(A cocky) Linus Torvalds talking on git:
[youtube]4XpnKHJAok8[/youtube]

Flame On!

Subversion vs git vs other?
Flame Control System