Code and Coffe: 2014

martes, 13 de mayo de 2014

Java Script : Regular Expressions Overview

Definition

In JavaScript , a regular expression is an object that describes a pattern of characters.

Commonly are used in functions for search o replace specific text , or pattern-matching (values validate)

Syntax

A regular expression basically is formed by : Pattern and Modifier

Pattern : specifies the pattern of an expression
Modifier: specify if a search should be global, case-sensitive, etc.

Modifiers can be:

Modifier	Description
i	Perform case-insensitive matching
g	Perform a global match (find all matches rather than stopping after the first match)
m	Perform multiline matchin

You can write a regular expression in Javascript in two modes:

use RegExp class :

var patt=new RegExp(pattern,modifiers);

or more simply (used for all examples in this article):

var patt=/pattern/modifiers;

Example:

Do global search of "hello" word:

var regExp = /hello/gi;

Where "hello" is a pattern and "g" and "i" are modifiers

Complete implementation can be:

function myFunction()
{
var str = "Hello , some body in home ? ";
var regExp = /hello/ig;
var result = str.match(regExp);
alert(result);
}

A regular expression pattern can be conformed by :

Brackets

Brackets are used to find a range of characters

Example :

Do global (modifier "g") search of number between 1 an 4 :

var regExp = /[1-4]/g;
Example: From value "9043192567" , the match is "43125"

Do global (modifier "g") search of any character from lowercase "a" to lowercase "z":

var regExp = /[a-z]/g;
Example: From value "HELLO kitty", the match value is "kitty"

Metacharacters

Metacharacters are characters with special meaning

Example:

Find a white space character:

var regExp = /\s/g;

Find a digit :

var regExp = /\d/g;

Quantifiers

Quantifiers match the preceding subpattern a certain number of times. The subpattern can be a single character, an escape sequence, a pattern enclosed by parentheses or a character set.

Example :

Match exactly all value in some text where "o" character appear 2 times :

var regExp = /o{2}/g
Example value : "tooth and nose" , the match value is "oo" from "tooth" word

Matches any digit that is not followed by "-" character :

var regExp = /\d(?!-)/g
Example value : "01-800-123-456" , the match value is 0,8,0,1,2,456

RegExp Object Method

In Javascript , RegExp object provides following methods :

exec() : Tests for a match in a string. Returns the first match

function myFunction() {

var str = "The best things in life are free";

var patt = new RegExp("e");

var res = patt.exec(str);

alert(res);

}

The result of res will be : "e"

test() : Tests for a match in a string. Returns true or false

function myFunction() {

var str = "The best things in life are free";

var patt = new RegExp("e");

var res = patt.exec(str);

alert(res);

}

The result of res will be : true

tostring(): Returns the string value of the regular expression

function myFunction() {

var patt = new RegExp("Hello World", "g");

var res = patt.toString();

alert(res);

}

The result of res will be : "/Hello World/g"

Common Examples:

Email Validation: Boolean function it return true if e-mail is a valid adress, return false if isn´t.

function emailValidation(email)
{
var regExp = new RegExp("^[\\w-\\.]+@([\\w-]+\\.)+[\\w-]{2,4}$","g");
alert(regExp.test(email));
}

Print Pages Validation: Boolean function it return true if received value match with the example values : 1,2,3-4,1 (like when you send to print pages)

function printPagesValidation(pages)
{
var regExp = new RegExp("^([\\d]+)$|([\\d]+)[-,]([\\d]+)$","g");
alert(regExp.test(pages));
}

References :

JavaScript RegExp Object : http://www.w3schools.com/jsref/jsref_obj_regexp.asp
Regular Expressions patterns: http://www.javascriptkit.com/javatutors/redev2.shtml

lunes, 14 de abril de 2014

ASP.Net MVC 3.0 with Microsoft Visual Web Developer 2010 Express (Part 1)

Hi, this is my first tutorial of 2014 , and i want to start with one of my favorite topic : MVC & ASP.Net

Points of this tutorial :

Fast (really very fast) Introduction to MVC

Show me the code !!!

Conclusions

Ok.. Here we go !!

Fast (really very fast) Introduction to MVC

MVC = Model, View and Controller

The Model-View-Controller (MVC) architectural pattern separates an application into three main components: the model, the view, and the controller. The ASP.NET MVC framework provides an alternative to the ASP.NET Web Forms pattern for creating Web applications. The ASP.NET MVC framework is a lightweight, highly testable presentation framework that (as with Web Forms-based applications) is integrated with existing ASP.NET features, such as master pages and membership-based authentication. The MVC framework is defined in the System.Web.Mvc assembly.

The MVC framework includes the following components:

Models. Model objects are the parts of the application that implement the logic for the application's data domain. Often, model objects retrieve and store model state in a database. For example, a Product object might retrieve information from a database, operate on it, and then write updated information back to a Products table in a SQL Server database.

In small applications, the model is often a conceptual separation instead of a physical one. For example, if the application only reads a dataset and sends it to the view, the application does not have a physical model layer and associated classes. In that case, the dataset takes on the role of a model object.

Views. Views are the components that display the application's user interface (UI). Typically, this UI is created from the model data. An example would be an edit view of a Products table that displays text boxes, drop-down lists, and check boxes based on the current state of a Product object.

Controllers. Controllers are the components that handle user interaction, work with the model, and ultimately select a view to render that displays UI. In an MVC application, the view only displays information; the controller handles and responds to user input and interaction. For example, the controller handles query-string values, and passes these values to the model, which in turn might use these values to query the database.

All this translates to the following : Independence of different layers , parallel development , Easy implementation of Unit Test, and business complexity management.