Pass rspec options from rake on command line

To pass rspec options from a rake task on command line,  use the env variable SPEC_OPTS. For example, to enable backtrace logging when running all spec tests:

rake SPEC_OPTS=-b



Ruby/Rails: Parse large XMLs (SAX parsers, Pull parsers) + example of Pull parser

When you have to parse huge XML files (hundreds of MB-like), loading the whole XML in memory is not an option.

Continue reading

Phone calling codes (aka International Dialing codes) – DB Dump / YML format

Parsed from: with Hpricot:

doc = Hpricot(open(""))
table = (doc/"table")[4]
by_country = {}'/tr').each {|tr| tr0 ='/td')[0] ; tr1 ='/td')[1]; by_country[tr0.inner_html.gsub(/<.*>/,  "")] ='/a').inner_html.gsub(" ", '').split(/\+/).select{|val| !val.empty?}.map(&:to_i) if tr1  } ; nil

Phone calling codes (MySQL dump)

Phone calling codes by country (YML format)

Why You Shouldn’t Use Float for Currency (floating point issues – explained for Ruby and RoR)

This article is a response to

It is a VERY BAD IDEEA to use floating point arithmetics to deal with currency. In most of the programming languages. Basically, because you’ll end up loosing money :). And this (on the great majority of cases) is not desirable 🙂 .

I’ll show you some magic (that you may try at home):
~$ ruby --version
ruby 1.8.7 (2009-06-12 patchlevel 174) [i486-linux]
~$ irb
irb(main):003:0> (10.12*100).to_i
=>; 1011

So, what just happened? Continue reading

Ruby on Rails Interview questions – update

Most of Google searches that hit my blog are about ‘ruby on rails interview questions‘.

Responding to this popular request 😉 , I will post 3 more questions that are related.

1. What type of data would you use to represent currency?

2. Why is it not a good practice to use float for currency?

3. Explain the following behaviour:

~$ ruby --version
ruby 1.8.7 (2009-06-12 patchlevel 174) [i486-linux]
~$ irb
irb(main):003:0> (10.12*100).to_i
=>; 1011

The answer – in my next post .

Rails Internationalization: currency format configuration

One of the nicest things in the built-in Rails internationalization features is the ability to format the currency according to the local culture (the number_to_currency method). For example, many european contries use ‘,’ as a separator and ‘.’ as a delimiter.

However, the examples presented in the help page ( are missing something essential.

 number_to_currency(1234567890.50, :unit => "&pound;", :separator => ",", :delimiter => "")
 # => &pound;1234567890,50
 number_to_currency(1234567890.50, :unit => "&pound;", :separator => ",", :delimiter => "", :format => "%n %u")
 # => 1234567890,50 &pound;

Why should i need a helper method where i can set all those parameters by hand?

Digging in the source code, i found how those settings can be put in the locale yml config file. Below is an example from my french localization file.

        delimiter: ','
        separator: '.'
        precision: 2
        format: '%n %u'

Complete Ubuntu install for a Ruby on Rails developer (utils, rails, ff addons)

This is a guide on creating a full-featured Ubuntu dev box for RoR. It assumes that you have already installed the latest version of Ubuntu.


sudo apt-get install build-essential
 Continue reading