dcadenas.blogspot.com

[Ruby] On Split an array into half

2010-10-02T15:07:20-07:00

If you are going to use this everywhere on many arrays on different places, it makes sense to extend Array:

class Array
  def split_in_two(first_chunk_size = self.size / 2)
   [self[0..first_chunk_size - 1], self[first_chunk_size..-1]]
  end
end

[1, 2, 3, 4, 5, 6].split_in_two 
> [[1, 2, 3], [4, 5, 6]]

[1, 2, 3, 4, 5, 6, 7].split_in_two 
> [[1, 2, 3], [4, 5, 6, 7]]

[1, 2, 3, 4, 5, 6, 7].split_in_two(5)
> [[1, 2, 3, 4, 5], [6, 7]]

[Ruby] On Code to detect the web browser

2008-08-29T17:19:25-07:00

@foca: A method extraction purpose is not only reusing code, which I agree it would be YAGNI, in this particular case, and in most cases, I do it for clarity, to improve readability.

A child can understand what remove_non_word_chars means but it will take longer to understand what \W+ and /[^a-z0-9]/+ means, even if you are an expert in regexps. It gives more importance to the purpose and the thought process that occurred when writing this code than the implementation (using regexps).

The method is more testable because I neither need to set the request nor I need to mock it. It's just a string manipulation without a dependency to a request.

The m flag had no sense to be there, I was doing some experiments before posting and I forgot to remove it, but I removed it one minute after posting the code!!!! how did you see it?

[Ruby] On Code to detect the web browser

2008-08-29T02:10:29-07:00

@chrismo: check that your code would break with the tests I'm posting here, I think they show the original desired behaviour

Some changes to foca's idea:
1) make it more testable
2) make it more declarative with some variables and a method extraction so that I don't have to remember what \W+ does again (I have an awful memory!!)
3) change the method name

I also added some Rspec tests for the next refactorings so it's easy for people to know what's the desired behaviour and to know they are not breaking anything

require 'rubygems'
require 'spec' 

def get_web_browser_id_string(user_agent = request.user_agent)
  web_browser_id_with_non_word_chars = ["Firefox/3", "Firefox/2", "MSIE 6", "MSIE 7", "Opera"].detect { |agent| user_agent =~ Regexp.new(agent)}
  remove_non_word_chars(web_browser_id_with_non_word_chars)
end

def remove_non_word_chars string_with_non_word_chars
  string_with_non_word_chars.gsub(/\W+/, "")
end

describe 'get_web_browser_id_string' do
  it 'should detect Firefox 3' do
    get_web_browser_id_string('Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.0.1) Gecko/2008070208 Firefox/3.0.1').should == 'Firefox3'
  end

  it 'should detect Firefox 2' do
    get_web_browser_id_string('Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8.1.13) Gecko/20080208 Mandriva/2.0.0.13-1mdv2008.1 (2008.1) Firefox/2.0.0.13').should == 'Firefox2'
  end

  it 'should detect MS Explorer 6' do
    get_web_browser_id_string('Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; NeosBrowser; .NET CLR 1.1.4322; .NET CLR 2.0.50727)').should == 'MSIE6'
  end

  it 'should detect MS Explorer 7' do
    get_web_browser_id_string('Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; .NET CLR 2.0.50727; Zune 2.0)').should == 'MSIE7'
  end

  it 'should detect Opera' do
    get_web_browser_id_string('Opera/9.20 (Macintosh; Intel Mac OS X; U; en)').should == 'Opera'
  end
end

[Ruby] Code to detect the web browser

2008-08-28T17:19:25-07:00

This is not my code but I want to see what can you do with it.

def test_web_browser()
  if request.env["HTTP_USER_AGENT"][/Firefox\/3/]=="Firefox/3"
    return "Firefox3"
  else
    if request.env["HTTP_USER_AGENT"][/Firefox\/2/]=="Firefox/2"
      return "Firefox2"
    else
      if request.env["HTTP_USER_AGENT"][/MSIE 6/]=="MSIE 6"
        return "MSIE6"
      else
        if request.env["HTTP_USER_AGENT"][/MSIE 7/]=="MSIE 7"
          return "MSIE7"
        else
          if request.env["HTTP_USER_AGENT"][/Opera/]=="Opera"
            return "Opera"
          end
        end
      end
    end
  end
end

[C#] On I hate to do this, but...

2008-07-16T02:04:07-07:00

    static class ExtensionsMethods
    {
        public static bool IsMultipleOf(this int number, int num)
        {
            return number % num == 0;
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            for (int i = 1; i <= 100; i++)
                Console.WriteLine(FizzBuzzify(i));

            Console.ReadKey();
        }

        static string FizzBuzzify(int i)
        {
            if (i.IsMultipleOf(3) && i.IsMultipleOf(5))
                return "FizzBuzz";

            if (i.IsMultipleOf(3))
                return "Fizz";

            if (i.IsMultipleOf(5))
                return "Buzz";

            return i.ToString();
        }
    }

[Ruby] On Human Date Method

2008-07-06T10:12:36-07:00

I share the scudco point of view.

def human_date date
  date = Date.parse(date) if date.is_a?(String)
  date.strftime date_format(date)
end

def human_date_with_time date
  date = Date.parse(date) if date.is_a?(String)
  date.strftime "#{date_format(date)} at #{time_format(date)}"
end

def date_format date
  "%B #{date.day}, %Y"
end

def time_format date
  "#{date.strftime('%I').to_i}:%M %p"
end