the actual meaning of “Merry Christmas”

Dec 14
2009
2
Comments 
import re
 
greeting = "Merry Christmas"
 
greeting_list = map(chr, [ord(i) - len(greeting) - 1 for i in greeting])
greeting_list = filter(lambda x: re.match('[a-z]|[A-Z]', x), greeting_list)
 
# greeting_list is set(['c', 'b', 'd', 'i', 'Q', 'U', 'Y', 'X'])
# the 1st 3 elements are not clear to me: c,b,d
# 'i' means 'I', 'Q' means 'question', 'U' means 'you', 'Y' means 'why', 'X' means 'Christmas'
# which makes the compound: 'I question you - why Christmas?'

Right?

Written by Vidul in: Python, news | Tags: | 2 Comments | More >>

Upgrade Trac seamlessly

Nov 28
2009
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Find your Trac path:

python -c’import trac;print trac’

Edit env.py on line 598:

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if needs_upgrade:
    try:
        os.system("/usr/bin/trac-admin %s upgrade" % env_path)
    except TracError:
        raise TracError(_('The Trac Environment needs to be upgraded.\n\n'
                              'Run "trac-admin %(path)s upgrade"', path=env_path))

Restart Trac daemon ot whatever http server is serving it.

Written by Vidul in: Python, Trac | Comments Off | More >>

The Alphabet

Oct 20
2009
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Python

import re
 
_char = re.compile(r'\w')
 
''.join([chr(i) for i in xrange(65,122) if _char.match(chr(i))])
 
# or just:
import string
 
string.ascii_letters
string.ascii_lowercase
string.ascii_uppercase

Ruby

(65..122).to_a.map{ |e| e.chr =~ /\w/ && e.chr }.compact.to_s

Perl

$chars .= chr() =~ /\w/ ? chr() : q{} for 65..122;

I don’t like the mess of Ruby, and Perl.

Written by Vidul in: Perl, Python, Ruby, chars | Comments Off | More >>

Delete Trac Tables

Aug 27
2009
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for i in `sqlite3 trac.db '.tables'`; do sqlite3 trac.db "delete from $i"; done
Written by Vidul in: Trac, scripts | Comments Off | More >>

Generate HTML with Javascript

Jul 29
2009
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sample HTML file

< !DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
   "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
      xml:lang="en">
  <head>
    <script src="jquery.min.js" type="text/javascript"></script>
  </head>
  <body>
    <div id="container"></div>
    <script src="gen.html.js" type="text/javascript"></script>
  </body>
</html>

sample JavaScript file (should be named gen.html.js)

$("#container").css({margin:"5% auto 5% auto",width:"70%",'max-width':"70%"});
$("#container").append("<div id='header'>this is the header</div>");
$("#container").append("<div id='body'>this is the body</div>");
$("#container").append("<div id='footer'>this is the footer</div>");
 
$("#header").css({width:"100%",height:"33px",'padding-top':"10px",'text-align':"center",border:"1px solid #777",background:"#ddd"});
$("#header").after("<div style='clear:both'>&&</div>");
$("#body").css({width:"100%",height:"50%",'madrgin-top':"2%",border:"1px solid #777",background:"#eee"});
$("#body").after("<div style='clear:both'>&nbsp;</div>");
$("#footer").css({width:"100%",height:"33px",'padding-top':"10px",'text-align':"center",border:"1px solid #777",background:"#ddd"});
 
$("#body").append("<p>1. sub body</p>");
$("#body").append("<p>2. sub body</p>");
$("#body p:first").css("text-decoration", "underline");
$("#body p:last").css("text-decoration", "overline");
Written by Vidul in: HTML, scripts | Comments Off | More >>

How to sort a file by its columns

Jun 04
2009
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# sort by user id
ruby -a -F: -ne 'puts $F.values_at(2, 0).join("\t")' '/etc/passwd' | sort -g
 
# sort by user home directory
ruby -a -F: -ne 'puts $F.values_at(5, 0).join("\t")' '/etc/passwd' | sort -g
 
# sort by username
ruby -a -F: -ne 'puts $F.values_at(0).join("\t")' '/etc/passwd' | sort -g
Written by Vidul in: Ruby, scripts, sorting | Comments Off | More >>

How to edit the ReCaptcha look

May 01
2009
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Take a look at recaptcha.js for DOM elements details.

Written by Vidul in: HTML | Tags: | Comments Off | More >>

Simple Ruby Text Parser

Mar 20
2009
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filename = "sample records.txt"
file = File.open(filename)
data = []
record = {}
 
class MyParse
  Tokens = [
    ### change the regular expressions accordingly ###
    ### sale date, sale time, sale address,
    [/^Sale:\s*(\d+\/\d+\/\d+)\s+(\S+\s+\w\w)\s+(.+?)\s*$/,
        lambda { |m| m.to_a &&
            {"sale date"=>m[1], "sale time"=>m[2], "sale address"=>m[3] } }],
    ### seller name, seller time, seller address
    [/^Seller:\s*(\d+\/\d+\/\d+)\s+(\S+\s+\w\w)\s+(.+?)\s*$/,
        lambda { |m| m.to_a &&
            {"seller date"=>m[1], "seller time"=>m[2], "seller address"=>m[3] } }],
    ### Trustor: trustor
    [/^Trustor:\s+(.+?)\s*$/,
        lambda { |m| m.to_a && {"trustor"=>m[1] } }],
  ]
 
  def self.read(text)
    parse(text)
  end
 
  protected
  def self.parse(text)
    text.each do |line|
      Tokens.each do |token|
        if m = token.first.match(line)
          return token.last.call(m)
        end
      end
    end
    nil
  end
 
end
 
begin
  while line = file.readline
    if line.match(/^\s*$/)
      record = {}
      next
    end
    line.sub!("\r", "")
    if record = MyParse.read(line)
      data.push(record)
    end
  end
rescue EOFError => e
  puts "'#{filename}': #{e}"
ensure
  file.close
end
 
puts data.inspect
 
exit(0)
Written by Vidul in: Ruby | Tags: | Comments Off | More >>

a quick remedy for ipod shuffle illnesses

Mar 18
2009
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Symptoms: one green light flash, followed by two green ones.

Conclusion: the player is dead.

Remedy: download ipod reset utility, reset the player and

# change _path_to_the_device_ with the real path (see `dmesg|tail`)
 
mount /dev/_path_to_the_device_  /mnt && cd /mnt
 
# download rebuild_db.py from http://shuffle-db.sourceforge.net/
# copy 'rebuild_db.py' in /mnt and create the dirs' structure
 
python -c '
import os
os.makedirs("iPod_Control/iTunes")
os.makedirs("Music")
'
 
cd /mnt && cp ~/Music/*.mp3 Music
python rebuild_db.py
cd .. && umount

That’s it.

P.S. you can format an ipod device as many times as you like,
just follow the above procedure to reset it.

Written by Vidul in: scripts | Comments Off | More >>

How to download an image from flickr

Mar 11
2009
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I wasn’t able to download a photo from flickr. It happened to be 1px transparent image over the other. Here is a simple scaper in cases of such “protection”:

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require 'rubygems'
require 'www/mechanize'
 
url = 'http://www.flickr.com/photos/46457493@N00/3162339409/in/set-72157612102050814/'
 
my_id = url.split("/")[-3]
agent  = WWW::Mechanize.new
page   = agent.get(url)
 
url   = page.search("//div[@id='photoImgDiv#{my_id}']/img").attr('src')
 
agent.get(url).save_as((File.basename(url)).split("?")[0])
Written by Vidul in: Ruby, scripts | Comments Off | More >>
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