The fastest method (according to the article) is:

def method6():
     return ''.join([`num` for num in xrange(loop_count)])

The article also lists the following, more common approach:

def method4():
    str_list = []
    for num in xrange(loop_count):
        str_list.append(`num`)

    return ''.join(str_list)

If I can find the spare time, I would really like to delve deeper in to the underlying reasons why the method6() is faster than the method 4().  In the meantime, I’ll continue to kick myself each time I throw a “+=” operator between two strings.

When I almost always see this:

It’s a matter of convenience for me.  It has nothing to do with any of the magic of Ruby, or my sadistic love for the whitespace of Python.  Instead, my choice is delegated to me by the sysadmins who control the boxes that I use.  On my personal machines I run both interpreters, and often jump between the two languages to keep my skillz up.  But, when it comes to production environments I’m a Pythonista.

And I’m OK with that.

Frozen Login Screen

I’ve been using Sun’s VirtualBox for about a month now on my Windows XP laptop and absolutely love it.  This morning, while trying to squeeze as much performance as I could out of it, I bumped the amount of my Ubuntu’s Virtual Machine’s Video Memory to 128MB and immediately noticed a problem:  when the VM would start up the screen was jumbled.  I bumped the setting back down to 64MB and things worked as they should.  If you are seeing something similar, try lowering the allotted video memory and see if that clears things up.

Fortunately, I spend a lot of time writing both the client side of my mobile web apps, as well as the server side components  that power them.  The easiest way I’ve found to quickly test the rendering of my output per device User-Agent is to install the User Agent Switcher component for Firefox.  This component allows you to quickly and easily  change the User-Agent header that your browser uses to identify itself to web servers.  With just a few clicks I can quickly run down a list of 10 devices and verify that device-specific logic is firing properly on the backend.  Additionally, I’ll often resize my Firefox window to the target device’s screen dimensions (e.g. 240×320) to get a rough approximation of the overall look and feel of the page.

While there is no real substitute for testing on real devices, this technique has proven useful to me and hopefully someone else will also find it useful.

Instead of this:

private Map map = new HashMap();
map.put(obj1, 3);
map.put(obj2, 4);
/*  yada yada yada */

You can do this:

private Map map = new HashMap(){{
put(obj1, 3);
put(obj2, 4);
/* yada yada yada */
}}

The first brace creates an anonymous inner class, and the second brace creates an initializer block that is executed when the anonymous class is created.

__

*it really wasn’t.

Bitpim is an open-source program that allows a user to manipulate data on a CDMA handset, including the phone book, wallpapers, ringtones, and in some cases, the filesystem. While poking around the application’s source, which is written in python, I found a great class that provides a quick way to access the phone’s manufacturer, ESN, and firmware revision. Yes, this information is available through a small set of keystrokes on CDMA handsets, but I have often found cases where I would still prefer to provide an app to a user and have it do all the dirty work.

The class is called “phone_detect.py” and it’s located under the /src/ in the source tree. All that it really does is act as a wrapper for the AT commands that are necessary to switch the phone into the correct mode and also to ask the phone for it’s configuration info. You can get a good understanding of what it’s doing by following the calls to __get_esn(). There are plenty of references available online that show the full range of AT commands that phones respond to.

To play with the class, you’ll need to get an install python. In addition to python, you will also need pySerial in order to interface with your serial port. Once you have your handset connected to your computer you can call use the class directly by calling DetectPhone().detect(). There’s an example of using this call in setphone_wizard.py if you need one. ]]> http://www.seancook.com/2008/07/03/programmatically-obtain-a-phones-esn/feed/ 0 http://www.seancook.com/2008/07/02/gzip-content-for-mobile-devices/ http://www.seancook.com/2008/07/02/gzip-content-for-mobile-devices/#comments Wed, 02 Jul 2008 18:31:39 +0000 Sean http://www.seancook.local/?p=11 Continue reading →]]> One of the easiest, most obvious ways to lower the data transfer footprint of your mobile apps is to compress data. For some reason, I still see mobile web decks that output XHTML-MP in plain text instead of very-easy-to-implement GZIP compression. I’ve implemented GZIP output on multiple J2EE projects with the help of Jayson Falkner’s excellent GZIPFilter which is available in his article Two Servlet Filters Every Web Application Should Have.

To implement the filter in your own projects, download the three pieces of the filter: GZIPFilter, GZIPResponseStream, GZIPResponseWrapper and save them in your project. Then, in your web.xml add the following entries:

Compress
GZIPFilter


Compress
*.do

Remember to adjust the url-pattern to what’s appropriate for your webapp. I typically map my Spring MVC dispatcher servlet to *.do, but that’s just a hangover from Struts.

Once you’ve redeployed your webapp you should verify that output is rendering correctly in a desktop client such as Firefox.

“Eat, drink, and be merry for tomorrow we die” – Tripping Billies

I caught DMB out at the Nissan Pavilion Saturday night for my 4th concert in 4 weeks (which brings my total ticket cost of this summer to more than $500). They sounded great, and as always I found myself in awe of Carter Beauford’s mad chops.

To use it, capify your working rails directory and then replace /config/deploy.rb with the code below:

set :user, '' #dreamhost username goes here
set :application, "" #dreamhost domain name goes here
set :repository, "" #path to your svn repo
set :scm_username, "" #svn username 

# =============================================================================
# You shouldn't have to modify the rest of these
# =============================================================================

role :web, application
role :app, application
role :db,  application, :primary => true

set :deploy_to, "/home/#{user}/#{application}"
# set :svn, "/path/to/svn"       # defaults to searching the PATH
set :use_sudo, false
# set :restart_via, :run
set(:scm_password) { Capistrano::CLI.password_prompt }

# saves space by only keeping last 3 when running cleanup
set :keep_releases, 3 

# issues svn export instead of checkout
set :checkout, "checkout" 

# keeps a local checkout of the repository on the server to get faster deployments
set :deploy_via, :remote_cache

ssh_options[:paranoid] = false

# =============================================================================
# OVERRIDE TASKS
# =============================================================================
namespace :deploy do

  desc "Restart Passenger"
  task :restart, :roles => :app do
    run "touch #{current_path}/tmp/restart.txt"
  end

  desc <<-DESC
    Deploy and run pending migrations. This will work similarly to the \
    `deploy' task, but will also run any pending migrations (via the \
    `deploy:migrate' task) prior to updating the symlink. Note that the \
    update in this case it is not atomic, and transactions are not used, \
    because migrations are not guaranteed to be reversible.
  DESC
  task :migrations do
    set :migrate_target, :latest
    update_code
    migrate
    symlink
    restart
  end

end