DZone Snippets: dynamic code

PHP Dynamic Checkbox Table Creator (data retrieved from MySQL DB)

dneuma (Daniel Neumann) — Fri, 02 May 2008 12:09:34 GMT

Hi All.
This is a function for Dynamically Create a Checbox Table retrieving information for from a MySQL Database.
As it is quite commented, it's also good for learning how this things work :)
Hope you find it useful.
Feedback is welcome.
Cheers
Dan



function dynamic_checkbox_table ($sql_str, $col_label, $col_name, $val_checked="S", $cant_cols_tbl=3){

/*

	by Daniel Neumann

	this script creates dynamically permite a table containing checkboxes 

	getting the data for the checkboxes from a MySQL DB

	$sql_str, SQL select string to retrieve data from DB (see example in last comment line)

	$col_label, DB column that has values for the checkbox label 

	$col_name, DB column that has values for the checkbox name

	$val_checked="S", value when checked (value="" attribute) it uses the same value for all of them. If you whish to use a dynamic value from a DB, you should comment the line (it´s explained next to the code in the middle of the function) and de-comment the other line (check the code,. you'll understand what I mean). Also, you should use this parameter to specify the column name for the values

	$cant_cols_tbl=3, quantity of columns for the table, it defaults to 3

	usage example: dynamic_checkbox_table("SELECT * FROM keywords", "Keyword", "ID_Keywrd");

*/

	

	//connect DB and run query

	$db="MyDB";

	$db_user="MyUser";

	$pass="MyPass";

	$host="localhost";

	@mysql_connect($host,$db_user,$pass);

	@mysql_select_db($db) or die ("cannot connect to DB");

	$q_resultado = mysql_query($sql_str);

	mysql_close();

	if (mysql_num_rows($q_resultado)==0) exit("no rows returned");

	

	$next_row = mysql_fetch_array($q_resultado); //fetch first row

	

	$output = "\n"; //open table tag

	do {

		$output .= "\n"; //open row tag

		for ($i=1 ; $i <= $cant_cols_tbl ; $i++ ){ //loops as many times as $cant_cols_tbl

			$row=$next_row; //assign $row, next row will be checking next one, that avoids starting a new row when it's gonna be empty

			$output .= "\n"; //close TD

		} //close for loop

		$output .= "\n"; //close row

	} while ($next_row); //close do-while (and checks if there's another row)

	$output .= ""; //open TD tag

			$output .= (!$row) ? "" : ''.$row[$col_label]; //create checkbox and data from $row (**** you should comment this line if you whish to use dynamic $val_checked****)

//			echo (!$row) ? "" : ''.$row[$col_label]; //create checkbox and data from $row (**** you should de-comment this line if you whish to use dynamic $val_checked****)

			$next_row = mysql_fetch_array($q_resultado); //retrieve next row

			$output .= "\n"; //close table

	return $output; 

}

The eval side of Ruby

jrobertson (James Robertson) — Fri, 29 Feb 2008 13:53:58 GMT

The eval method in Ruby executes the code from within a string.



eval("puts 'Hello World'")

output:



Hello World

Pull JavaScript code dynamically into your web page at run-time.

jrobertson (James Robertson) — Fri, 21 Dec 2007 22:36:04 GMT

Using the JavaScript keyword Eval() with AJAX makes it possible to dynamically add JavaScript code at run-time to your web page.

Here's the complete code dynalert.html, dynalert.js, and dynalert.cgi

file:dynalert.html



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



	

		dynalert

		

		

	



	

123

file: dynalert.js



function populatePage(results){

  eval(results);

}



//send the update

function update() {



	var strServer = "dynalert.cgi";

	url2 = "";

	SubmitRBData(strServer,"?" + url2);



}



function SubmitRBData(strUrl, strPostFields) {

	http.open("GET", strUrl + strPostFields, true);

	http.onreadystatechange = handleHttpResponse;

	http.send(null);

}

function handleHttpResponse() {



	if (http.readyState == 4) {

		if (http.status == 200)

		{

		results = http.responseText;

		populatePage(results); // string response

		}

	}



}



function getHTTPObject() {



	var objXMLHttp=null



	if (window.XMLHttpRequest)

	{

		objXMLHttp=new XMLHttpRequest()

	}

	else if (window.ActiveXObject)

	{

		objXMLHttp=new ActiveXObject("Microsoft.XMLHTTP")

	}



return objXMLHttp



}



var http = getHTTPObject(); // We create the HTTP Object

file:dynalert.cgi



#!/usr/bin/ruby

# dynalert.cgi



require 'cgi'



cgi = CGI.new



#title = cgi['title']



puts "Content-Type: text/html"

puts

puts "function transcript(){ alert('and Bob said this idea might work.');}"

puts "alert('this is a success');"

puts "alert('we can now pass back anything we like');"

puts "transcript();"

puts "oNew = document.createElement('strong');"

puts "oNew.innerHTML = 'yes - this is bold text';"

puts "document.getElementById('i1').appendChild(oNew);"

The 0-1 Knapsack Problem in C

scvalex (Alexandru Scvortov) — Tue, 20 Nov 2007 17:17:50 GMT

This is a dynamic-programming algorithm implementation for solving the the 0-1 Knapsack Problem in C.

Further explanation is given here.



#include 



#define MAXWEIGHT 100



int n = 3; /* The number of objects */

int c[10] = {8, 6, 4}; /* c[i] is the *COST* of the ith object; i.e. what

				YOU PAY to take the object */

int v[10] = {16, 10, 7}; /* v[i] is the *VALUE* of the ith object; i.e.

				what YOU GET for taking the object */

int W = 10; /* The maximum weight you can take */ 



void fill_sack() {

	int a[MAXWEIGHT]; /* a[i] holds the maximum value that can be obtained

				using at most i weight */

	int last_added[MAXWEIGHT]; /* I use this to calculate which object were

					added */

	int i, j;

	int aux;



	for (i = 0; i <= W; ++i) {

		a[i] = 0;

		last_added[i] = -1;

	}



	a[0] = 0;

	for (i = 1; i <= W; ++i)

		for (j = 0; j < n; ++j)

			if ((c[j] <= i) && (a[i] < a[i - c[j]] + v[j])) {

				a[i] = a[i - c[j]] + v[j];

				last_added[i] = j;

			}



	for (i = 0; i <= W; ++i)

		if (last_added[i] != -1)

			printf("Weight %d; Benefit: %d; To reach this weight I added object %d (%d$ %dKg) to weight %d.\n", i, a[i], last_added[i] + 1, v[last_added[i]], c[last_added[i]], i - c[last_added[i]]);

		else

			printf("Weight %d; Benefit: 0; Can't reach this exact weight.\n", i);



	printf("---\n");



	aux = W;

	while ((aux > 0) && (last_added[aux] != -1)) {

		printf("Added object %d (%d$ %dKg). Space left: %d\n", last_added[aux] + 1, v[last_added[aux]], c[last_added[aux]], aux - c[last_added[aux]]);

		aux -= c[last_added[aux]];

	}



	printf("Total value added: %d$\n", a[W]);

}



int main(int argc, char *argv[]) {

	fill_sack();



	return 0;

}

dynamic rails img headers

jm3 (john manoogian III) — Tue, 06 Nov 2007 00:52:30 GMT

// description of your code here



find views -name [a-z]\*rhtml | xargs -n1 grep -H "@page_title" | grep -v "<%" | sed "s/\@page_title = //" | sed "s/rhtml/png/" | sed "s:views/::" | sed "s:/:_:g" | sed "s:^:public/images/beta/headers/hdr_:" | sed "s/  //g"

Add a jar file to Java load path at run time

mikewilsonuk (Mike Wilson) — Fri, 23 Feb 2007 15:24:18 GMT

Sometimes it is necessary to amend the class load path at run time. For example, dynamically adding jar files containing user-configurable JDBC data sources. The way this is done is truly monstrous -- the URL Path format was only revealed when a colleague looked into the Java library sources.



import java.net.URL;

import java.io.IOException;

import java.net.URLClassLoader;

import java.net.MalformedURLException;



public class JarFileLoader extends URLClassLoader

{

    public JarFileLoader (URL[] urls)

    {

        super (urls);

    }



    public void addFile (String path) throws MalformedURLException

    {

        String urlPath = "jar:file://" + path + "!/";

        addURL (new URL (urlPath));

    }



    public static void main (String args [])

    {

        try

        {

            System.out.println ("First attempt...");

            Class.forName ("org.gjt.mm.mysql.Driver");

        }

        catch (Exception ex)

        {

            System.out.println ("Failed.");

        }



        try

        {

            URL urls [] = {};



            JarFileLoader cl = new JarFileLoader (urls);

            cl.addFile ("/opt/mysql-connector-java-5.0.4/mysql-connector-java-5.0.4-bin.jar");

            System.out.println ("Second attempt...");

            cl.loadClass ("org.gjt.mm.mysql.Driver");

            System.out.println ("Success!");

        }

        catch (Exception ex)

        {

            System.out.println ("Failed.");

            ex.printStackTrace ();

        }

    }

}

PHP: Dynamically call a function from list of allowed actions

alexwilliams (Alex Williams) — Wed, 03 Jan 2007 12:15:14 GMT

This function simply calls another function based on the argument, assuming that argument ($action) is in the "allowed" list of actions.

settings-config.php



$settings['actions'] = "list,view,delete,update";

Catalog-class.php



public function process_action($action) {

	global $settings;

	

	$allowed_actions = explode(",",$settings['actions']);

	if (is_numeric(array_search($action, $allowed_actions))) {

		$f_name = "product_" . $action;

		$this->$f_name();

	} else {

		$this->error_msg = 'ACTION_NOT_ALLOWED';

	}

}

private function product_list() {

}

private function product_view() {

}

private function product_delete() {

}

private function product_update() {

}

private function product_create() {

}

Even if product_create() exists, if you do process_action('create'), it will not work... it's basically like a function wrapper.. or something like that...

UPDATE: Yes I know I could have created an array like $settions['actions'] = array('list','view','delete','update'); but I've modified this code a bit for snippet/display purposes... anyways this is just a reminder for myself, not of actual use or interest for others... comments are welcome though :D

go from model to associated table name and back

moneypenny () — Sat, 03 Jun 2006 00:50:06 GMT

Given a table object, it returns the related string object; e.g. SubAttribute => 'sub-attribute'. Useful if you want to make a list of all your tables with perhaps their fields listed out to the side.



def stringify_table( table, replace_char = '-', pluralize = false )

  string = table.to_s.gsub( /([A-Za-z])([A-Z])/, '\1' << replace_char.to_s << '\2' )

  string = string.pluralize if pluralize

  string

end

Given a string akin to the name of a table, it returns the related table object; e.g. 'sub_attributes' => SubAttribute.



def tablify_string( string )

  eval( string.to_s.gsub( /_id/, '' ).singularize.split( '_' ).collect { |word| word.capitalize }.join )

end

A dynamic form of the class statement.

korakot (Korakot Chaovavanich) — Fri, 17 Mar 2006 20:21:27 GMT

These 2 methods are equivalent.



# method 1

class X(object):

    a = 1



# method 2

X = type('X', (object,), dict(a=1))

Gmail-Like Incremental Search //JavaScript Class

jonasraoni (Jonas Raoni Soares Silva) — Fri, 09 Sep 2005 07:41:46 GMT

Implements a GMail-like auto-complete.

[UPDATED CODE AND HELP CAN BE FOUND HERE]

@REQUIRES Event-Listener



//Requires http://www.jsfromhell.com/geral/event-listener



//+ Jonas Raoni Soares Silva

//@ http://jsfromhell.com/dhtml/incremental-search [v1.0]



IncrementalSearch = function( input, callback, className ){

	var i, o = ( o = this, o.l = [], o.i = input, o.c = null, o.s = { e: null, i: -1 }, o.f = callback || function(){}, o.n = className || "", o );

	for( i in { keydown: 0, focus: 0, blur: 0, keyup: 0, keypress: 0 } )

		addEventListener( o.i, i, function( e ){ o.handler.call( o, e ); } );

};

with( { p: IncrementalSearch.prototype } ){

	(p.constructor.fadeAway = function( o ){

		o instanceof Object ? ( this.trash = this.trash || [] ).push( o ) && setTimeout( this.fadeAway, 200 ) : arguments.callee.c.trash.pop().hide();

	}).c = p.constructor;

	p.callEvent = function( e ){ this[e] && this[e].apply( this, [].slice.call( arguments, 1 ) ); };

	p.highlite = function( e ){ ( this.s.e && ( this.s.e.className = "normal" ), ( this.s = { e: e, i: e.listindex } ).e.className += " highlited", this.callEvent( "onhighlite", this.l[ this.s.i ], this.s.e.d ) ); };

	p.select = function(){ this.s.i + 1 && ( this.i.value = this.l[ this.s.i ], this.callEvent( "onselect", this.i.value, this.s.e.d ), this.hide() ); };

	p.hide = function(){ ( this.c && this.c.parentNode.removeChild( this.c ), this.c = null, this.l = [], this.s = { e: null, i: -1 }, this.callEvent( "onhide" ) ); };

	p.next = function(){ var e = ( e = this.s.e ) ? e.nextSibling || e.parentNode.firstChild : null; e && this.highlite( e ); };

	p.previous = function(){ var e = ( e = this.s.e ) ? e.previousSibling || e.parentNode.lastChild : null; e && this.highlite( e ); };

	p.handler = function( evt ){

		var o = this, t = evt.type, k = evt.key, e = /span/i.test( ( e = evt.target ).tagName ) ? e.parentNode : e;

		t == "keyup" ? k != 40 && k != 38 && k != 13 && o.show()

		: t == "keydown" ? ( k == 40 && o.next() ) || ( k == 38 && o.previous() )

		: t == "keypress" ? k == 13 && !evt.preventDefault() && o.select()

		: t == "blur" ? o.constructor.fadeAway( o )

		: t == "click" ? o.select()

		: t == "focus" ? o.show()

		: o.highlite( e );

	};

	p.show = function(){

		var cS, found = 0, o = this, i = o.i, iV = i.value, d = document, c = ( o.hide(), o.c = d.body.appendChild( d.createElement( "div" ) ) );

		( c.className = o.n, cS = c.style, cS.display = "none", cS.position = "absolute", o.callEvent( "onshow" ) );

		o.f.call( function( s, x, data ){

			if( !( x.length == undefined ? ( x = [x] ) : x ).length )

				return;

			var j, l = 0, i = o.l.length, e = c.appendChild( d.createElement( "div" ) );

			for( j in ( o.l[i] = s, e.className = "normal", e.d = data, e.listindex = i, !found && i == o.s.i && ++found && o.highlite( e ), x ) )

				e.appendChild( d.createTextNode( s.substring( l, x[j] ) ) ).parentNode.appendChild( d.createElement( "span" ) ).appendChild( d.createTextNode( s.substring( x[j], l = x[j] + iV.length ) ) ).parentNode.className = "selectedText";

			for( x in ( e.appendChild( d.createTextNode( s.substr( l ) ) ), { click: 0, mouseover: 0 } ) )

				addEventListener( e, x, function( e ){ o.handler.call( o, e ); } );

		}, iV );

		if( !c.childNodes.length )

			return o.hide();

		for( var x = i.offsetLeft, y = i.offsetTop + i.offsetHeight; i = i.offsetParent; x += i.offsetLeft, y += i.offsetTop );

		( cS.display = "block", cS.left = x + "px", cS.top = y + "px", !found && o.highlite( c.firstChild ) );

	};

}

Example









	

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