DZone Snippets: search code

Searching through your Twitter archive

jrobertson (James Robertson) — Wed, 20 Feb 2008 12:55:59 GMT

This Ruby code downloads previous twitter entries as html files to a local file directory.



(1..5).each {|i| `wget --user=jrobertson --password=secret http://twitter.com/account/archive?page=#{i}`}

then using grep -i * you can search for anything you've twittered in the past.

Note: Use Wget sparingly.

Disjoint Set Class in Ruby

dr_saturn (Stuart Coyle) — Sun, 10 Feb 2008 02:49:59 GMT

A disjoint Set can be used for creating minimal spanning trees.
The union-find algorithm is fast, faster than linked lists for some uses.
See: Wikipedia Disjoint Set

It's fast and simple. Just add a DisjointSetNode object to the
objects that you want to create a tree of.



# This is a disjoint set implementing union-find

# It can be used for generating a minimal spanning

# tree using Kruskal's algorithm.

# http://en.wikipedia.org/wiki/Kruskal's_algorithm



class DisjointSetNode

  attr_accessor :parent, :rank



  def initialize

    @parent = self

    @rank = 0

  end



  # An optimised union by rank. Attaches smaller tree to larger.

  def union(other)

    self_root = self.find

    other_root = other.find

    if self_root.rank > other_root.rank

      other_root.parent = self_root

    elsif self_root.rank < other_root.rank

      self_root.parent = other_root

    elsif self_root != other_root

      other_root.parent = self_root

      self_root.rank += 1

    end

  end



  def find

    if self.parent === self

      self

    else

      self.parent = self.parent.find

    end

  end



end   # class DisjointSetNode

Some simple test code:



require 'disjointsetnode'

require 'test/unit'

require 'test/unit/ui/console/testrunner'



    class DisjointSetTest < Test::Unit::TestCase

      N_Nodes = 1000



      def setup

        @nodes = Array.new

        (1..N_Nodes).each do |node|

        @nodes << DisjointSetNode.new

        end

      end



      # def teardown

      # end



      def test_creation

        @nodes.each do |node|

          assert !node.nil?, "A Node is nil!"

        end

      end



      def test_initial_values

        @nodes.each do |node|

          assert node.parent === node, "self #{node}, parent #{node.parent} not equal."

          assert node.rank == 0, " A node's rtank is not 0."

        end

      end



      def test_union

        # Join all nodes in sequence

        @nodes.each do |node|

          if !@lastnode.nil?

            node.union(@lastnode)

            node_f = node.find

            lnode_f = @lastnode.find

            assert node_f == lnode_f, "Join not completed: node_f: #{node_f}, lnode_f: #{lnode_f}"

          end

          @lastnode = node

        end

      end



      def test_random_union

        (1..N_Nodes-1).each do |n|

          node = @nodes[n]

          other = @nodes[rand(N_Nodes-1)]

          node.union(other)

          node_f = node.find

          onode_f = other.find

          assert node_f == onode_f, "Join not completed: node_f: #{node_f}, onode_f: #{onode_f}"

        end

      end

    end



# This runs the tests for ya! 

Test::Unit::UI::Console::TestRunner.run(DisjointSetTest)

Add a Google custom search facility to your website

jrobertson (James Robertson) — Sun, 06 Jan 2008 13:48:50 GMT

This HTML page displays a basic search page similar to http://www.google.com/ however this search page will only search for results from http://snippets.dzone.com.



    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">



abc

I stumbled across the hidden query field while I was looking for ways to perform custom search without the need for JavaScript. If you are interested in Google's official custom search engine on your site go to http://www.google.com/cse

* update 8-Jan-08 2:01pm *
Here's a more advanced example from someone's blog titled 'Fine-tuning Custom Google Search' http://snipr.com/1wppb [blogs.salon.com]



;

;

 






>span class="small">

Search blogs.salon.com

Search the Web

Tutor search

grahamgilbert (Graham Gilbert) — Wed, 05 Dec 2007 16:20:24 GMT

// Search results page - formatting html has been omited.





		// The basic SELECT statement

		$select = 'SELECT id, title, forename, surname, userlevel';

		$from = ' FROM users';

		$where = " WHERE userlevel='2'";



		$forename = $_POST['forename'];

		if ($forename !='') { //Forename was specified

		$where .= " AND forename LIKE '%$forename%'";



		$surname = $_POST['surname'];

		if ($surname !='') { //Surnamename was specified

		$where .= " AND surname LIKE '%$surname%'";

		}

		?>



		$users = @mysql_query($select . $from . $where);

	if (!$users) {

	exit ('Unable to abtain user list from the database');

	}



	?>

	



	while ($user = mysql_fetch_array($users)) {

	echo "\n";

	$id = $user['id'];

	$username = htmlspecialchars($user['username']);

	$title = htmlspecialchars($user['title']);

	$forename = htmlspecialchars($user['forename']);

	$surname = htmlspecialchars($user['surname']);


	echo "\n";

	echo "\n";

	echo "\n";

	}

	?>


	Username Title Forename Surname Options

	
$username $title $forename $surname Edit | Delete

Username	Title	Forename	Surname	Options
$username	$title	$forename	$surname	Edit \| Delete

Babelfish translate

griflet (guillaume riflet) — Thu, 05 Jul 2007 20:48:59 GMT

Ok, so maybe some of you might think that Babelfish's the best translator out there. I don't know about that , but I do know where my towel is ;)
So, boys and girls, here's the bookmarklet that allows to translate your current web-page using the babelfish translation engine.



javascript:location.href='http://babelfish.altavista.com/babelfish/tr?trurl='+encodeURIComponent(location.href)+'&lp=%s&btnTrUrl=Translate'

To make it useful, save it as a bookmark in FF (or as a new search engine in Opera) and give it a keyword/shortcut by editing the bookmark's properties in FF (or the search properties in Opera). Let's call him, say 'bf', that should do it.

Here are some examples:



bf en_fr

bf fr_en

bf en_ja

Enjoy!
G.R.

Fast stop word detection in Ruby

peter (Peter Cooperx) — Mon, 02 Jul 2007 03:10:16 GMT

Requires BloominSimple (a pure Ruby Bloom filter class).

List of stop words obtained from http://www.dcs.gla.ac.uk/idom/ir_resources/linguistic_utils/stop_words

# Detect stop words QUICKLY

# Uses a bloom filter instead of searching literally through a list of stopwords

# for > 3x speed increase

# 

#    using bloom filter: 2.580000   0.030000   2.610000 (  2.698829)

#  using literal search: 7.850000   0.120000   7.970000 (  8.181684)





require 'bloominsimple'

require 'digest/sha1'

require 'pp'



# Create a simple bloom filter that uses a SHA1 hash (more effective than BloominSimple's default hashing)

b = BloominSimple.new(50000) do |word|

  Digest::SHA1.digest(word.downcase.strip).unpack("VVV")

end



# Add stopwords to the bloom filter!

stopwords = []

File.open('stopwords').each { |a| b.add(a); stopwords << a.downcase.strip }



# Read in a whole dictionary of regular words

words = File.open('/usr/share/dict/words').read.split.collect{|a| a.downcase.strip }



# Define two ways to detect stopwords for comparison..

using_filter = lambda { |word| b.includes?(word) }

using_array = lambda { |word| stopwords.include?(word.downcase.strip) }

techniques = [using_filter, using_array]



# Run stopword comparisons with both techniques

t = techniques.collect { |l| words.collect { |a| l[a] } }



# See how effective the bloom filter has been compared to the literal search

if t[0] == t[1]

  puts "GOOD"

else

  words.zip(t[0],t[1]).each do |x|

    puts x.first if x[1] != x[2]

  end

end



# Now do speed benchmarks..

techniques.each { |l| puts Benchmark.measure { words.each { |a| l[a] } } }

Array Search Prototype

pcx99 (Patrick) — Mon, 05 Mar 2007 18:39:38 GMT

This prototype extends the Array object to allow for searches
within the Array. It will return false if nothing is found. If
item(s) are found you'll get an array of indexes back which matched
your search request. It accepts strings, numbers, and regular expressions as search
criteria. 35 is different than '35' and vice-versa.



// Examples

var test=[1,58,'blue','baby','boy','cat',35,'35',18,18,104]

result1=test.find(35);    //returns 6

result2=test.find(/^b/i); //returns 2,3,4

result3=test.find('35');  //returns 7

result4=test.find(18);    // returns 8,9

result5=test.find('zebra'); //returns false



Array.prototype.find = function(searchStr) {

  var returnArray = false;

  for (i=0; i    if (typeof(searchStr) == 'function') {

      if (searchStr.test(this[i])) {

        if (!returnArray) { returnArray = [] }

        returnArray.push(i);

      }

    } else {

      if (this[i]===searchStr) {

        if (!returnArray) { returnArray = [] }

        returnArray.push(i);

      }

    }

  }

  return returnArray;

}

J2ME - Create Service Bluetooth

whitetiger () — Fri, 23 Feb 2007 14:22:23 GMT

// Create Service Bluetooth



import javax.bluetooth.DiscoveryAgent;

import javax.bluetooth.LocalDevice;

import javax.microedition.io.Connector;

import javax.microedition.io.StreamConnection;

import javax.microedition.io.StreamConnectionNotifier;



public class ServerChat

{

	private static final String CHATTANDO_UUID = "A1A2A3A4A5A6A7A8A9A0B1B2B3B4B5B6";

	private static final String CHATTANDO_SERVICE = "Chattando";

	

	private boolean isReady = false;

	

	private StreamConnection stream_connection;

	private StreamConnectionNotifier stream_connection_notifier;

	

	public ServerChat()

	{

		startServerChatBluetooth();

	}

	

	// Apre il servizio per la Chat

	public void startServerChatBluetooth()

	{

		new Thread()

		{

			public void run()

			{

				try

				{

					LocalDevice.getLocalDevice().setDiscoverable(DiscoveryAgent.GIAC);

				}

				catch(Exception error)

				{

					error.printStackTrace();

				}

				

				try

				{

					stream_connection_notifier = (StreamConnectionNotifier) Connector.open("btspp://localhost:" + CHATTANDO_UUID + ";name=" + CHATTANDO_SERVICE);

				}

				catch(Exception error)

				{

					error.printStackTrace();

				}

				

				stopServerChatBluetooth();

				

				// Mette in ascolto il Server della Chat

				isReady = true;

				

				try

				{

					while(isReady)

					{

						System.out.println("Sono in ascolto...");

						

						stream_connection = stream_connection_notifier.acceptAndOpen();

						

						System.out.println("Client Connected");

					}

				}

				catch(Exception error)

				{

					error.printStackTrace();

				}

			}

			

		}.start();

	}



	// Chiude il servizio per la Chat

	public void stopServerChatBluetooth()

	{

		if(isReady)

		{

			isReady = false;

			

			try

			{

				stream_connection_notifier.close();

			}

			catch(Exception error)

			{

				error.printStackTrace();

			}

		}

	}

}

J2ME - Search Service Bluetooth

whitetiger () — Fri, 23 Feb 2007 14:21:30 GMT

// Example Search Service Bluetooth



import java.util.Vector;



import javax.bluetooth.DeviceClass;

import javax.bluetooth.DiscoveryAgent;

import javax.bluetooth.DiscoveryListener;

import javax.bluetooth.LocalDevice;

import javax.bluetooth.RemoteDevice;

import javax.bluetooth.ServiceRecord;

import javax.bluetooth.UUID;



public class ClientChat implements DiscoveryListener

{

	private static final String CHATTANDO_UUID = "A1A2A3A4A5A6A7A8A9A0B1B2B3B4B5B6";

	private static final String CHATTANDO_SERVICE = "Chattando";



	protected Chattando midlet;

	

	private boolean searchDone = false;

	

	private DiscoveryAgent discovery_agent;

	

	private Vector remote_device;

	private Vector device_found;

	

	public ClientChat(Chattando midlet)

	{

		this.midlet = midlet;

		

		startScanBluetoothDevices();

	}

	

	// Avvia la ricerca dei dispositivi Bluetooth

	public void startScanBluetoothDevices()

	{

		try

		{

			remote_device = new Vector();

			device_found = new Vector();

			

			discovery_agent = LocalDevice.getLocalDevice().getDiscoveryAgent();

			discovery_agent.startInquiry(DiscoveryAgent.GIAC, this);

		}

		catch(Exception error)

		{

			error.printStackTrace();

		}

	}

	

	// Stoppa la ricerca dei dispositivi Bluetooth

	public void stopScanBluetoothDevices()

	{

		discovery_agent.cancelInquiry(this);

	}



	public void deviceDiscovered(RemoteDevice btDevice, DeviceClass cod) 

	{

		// Aggiungo il dispositivo solo se e' un computer (0x0100) o un cellulare (0x0200)

		if(cod.getMajorDeviceClass() == 0x0100 || cod.getMajorDeviceClass() == 0x0200)

			remote_device.addElement(btDevice);

	}



	public void inquiryCompleted(int discType)

	{

		switch(discType)

		{

			case DiscoveryListener.INQUIRY_COMPLETED:

														System.out.println("Device Search Completed");

														

														break;

				

			case DiscoveryListener.INQUIRY_ERROR:

														System.out.println("Device Search Error");

														

														break;

				

			case DiscoveryListener.INQUIRY_TERMINATED:

														System.out.println("Device Search Terminated");

														

														break;

		}

		

		try

		{

			for(int i=0, cnt=remote_device.size(); i			{

				discovery_agent.searchServices(new int[]{ 0x0100, 0x0200 }, new UUID[]{ new UUID(0x0003), new UUID(CHATTANDO_UUID, false) }, (RemoteDevice) remote_device.elementAt(i), this);

				waitForSearchDone();

			}

		}

		catch(Exception error)

		{

			error.printStackTrace();

		}

	}



	// Aspetta che la ricerca dei servizi per il dispositivo sia terminata

	private void waitForSearchDone()

	{

		searchDone = false;

		

		try

		{

			while(!searchDone)

			{

				synchronized(this)

				{

					this.wait();

				}

			}

		}

		catch(Exception error)

		{

			

		}

	}

	

	public void serviceSearchCompleted(int transID, int respCode)

	{

		switch(respCode)

		{

			case DiscoveryListener.SERVICE_SEARCH_COMPLETED:

																		System.out.println("Service Search Completed");

																		

																		break;

				

			case DiscoveryListener.SERVICE_SEARCH_DEVICE_NOT_REACHABLE:

																		System.out.println("Service Search Device not Reachable");

																		

																		break;

				

			case DiscoveryListener.SERVICE_SEARCH_ERROR:

																		System.out.println("Service Search Error");

																		

																		break;

				

			case DiscoveryListener.SERVICE_SEARCH_NO_RECORDS:

																		System.out.println("Service Search No Records");

																		

																		break;

				

			case DiscoveryListener.SERVICE_SEARCH_TERMINATED:

																		System.out.println("Service Search Terminated");

																		

																		break;

		}

		

		searchDone = true;

		

		// Risveglia il processo in attesa del completamento della ricerca dei servizi per un dispositivo

		synchronized(this)

		{

			this.notifyAll();

		}

	}



	public void servicesDiscovered(int transID, ServiceRecord[] servRecord)

	{

		for(int i=0, cnt=servRecord.length; i		{

			if(((String) servRecord[i].getAttributeValue(0x0100).getValue()).equalsIgnoreCase(CHATTANDO_SERVICE))

			{

				device_found.addElement(servRecord[i].getHostDevice());

			}

		}

	}

}

binarysearch.scm

mcandre (Andrew Pennebaker) — Mon, 19 Feb 2007 00:38:41 GMT

// Binary Search



; Andrew Pennebaker

; 18 Feb 2007

; License: GPL

; URL: http://snippets.dzone.com/posts/show/3535



(define binary-search

	(lambda (ls value low high)

		(let ((mid (floor (/ (+ low high) 2))))

			(cond

				((> low high) -1)

				((= (list-ref ls mid) value) mid)

				((> (list-ref ls mid) value) (binary-search ls value low (- mid 1)))

				((< (list-ref ls mid) value) (binary-search ls value (+ mid 1) high))))))