Tutorial by Examples: n

One common use case for generators is reading a file from disk and iterating over its contents. Below is a class that allows you to iterate over a CSV file. The memory usage for this script is very predictable, and will not fluctuate depending on the size of the CSV file. <?php class CsvReade...

To be able to use JDBC you need to have the JDBC driver of your database on the class path of your application. There are multiple ways to connect to a database, but the common ways are to either use the java.sql.DriverManager, or to configure and use a database specific implementation of javax.sql...

The AppCompat Support Library defines several useful styles for Buttons, each of which extend a base Widget.AppCompat.Button style that is applied to all buttons by default if you are using an AppCompat theme. This style helps ensure that all buttons look the same by default following the Material D...

There are only two string operators: Concatenation of two strings (dot): $a = "a"; $b = "b"; $c = $a . $b; // $c => "ab" Concatenating assignment (dot=): $a = "a"; $a .= "b"; // $a => "ab"

$a = "some string"; results in $a having the value some string. The result of an assignment expression is the value being assigned. Note that a single equal sign = is NOT for comparison! $a = 3; $b = ($a = 5); does the following: Line 1 assigns 3 to $a. Line 2 assigns 5 to $a....

The combined assignment operators are a shortcut for an operation on some variable and subsequently assigning this new value to that variable. Arithmetic: $a = 1; // basic assignment $a += 2; // read as '$a = $a + 2'; $a now is (1 + 2) => 3 $a -= 1; // $a now is (3 - 1) => 2 $a *= 2; //...

The order in which operators are evaluated is determined by the operator precedence (see also the Remarks section). In $a = 2 * 3 + 4; $a gets a value of 10 because 2 * 3 is evaluated first (multiplication has a higher precedence than addition) yielding a sub-result of 6 + 4, which equals to 10...

Left association If the preceedence of two operators is equal, the associativity determines the grouping (see also the Remarks section): $a = 5 * 3 % 2; // $a now is (5 * 3) % 2 => (15 % 2) => 1 * and % have equal precedence and left associativity. Because the multiplication occurs first ...

Simple check To check if constant is defined use the defined function. Note that this function doesn't care about constant's value, it only cares if the constant exists or not. Even if the value of the constant is null or false the function will still return true. <?php define("GOOD&quo...

Constants are created using the const statement or the define function. The convention is to use UPPERCASE letters for constant names. Define constant using explicit values const PI = 3.14; // float define("EARTH_IS_FLAT", false); // boolean const "UNKNOWN" = null; // null d...

Filter code: angular.module('myModule', []).filter('multiplier', function() { return function(number, multiplier) { if (!angular.isNumber(number)) { throw new Error(number + " is not a number!"); } if (!multiplier) { multiplier = 2; } return numbe...

If you want to include PHP code in your HTML file and you don't want to rename the file type from .html or .htm to .php, the below allows your HTML file to parse your PHP code correctly. AddHandler application/x-httpd-php .html .htm

404 responses are returned when a resource is not found on the server, in Symfony this status can be created by throwing a NotFoundHttpException exception. To avoid an extra use statement inside a controller use the createNotFoundException() provided by the Controller class <?php namespace Bu...

Implementing IErrorHandler for WCF services is a great way to centralize error handling and logging. The implementation shown here should catch any unhandled exception that is thrown as a result of a call to one of your WCF services. Also shown in this example is how to return a custom object, and h...

To assert that a value is either true or false,: Assert.IsFalse(Settings.DoBadThings, "Bad things should not happen, disable DoBadThings."); Assert.IsTrue(magicNumber =< 42, "The magic number is greater than 42!"); You can also pass formatting parameters for the exception...

ResultNotNull() checks to see if the object passed in is not null. If the object and message are not null it will then simply return the object that was passed in, otherwise it will throw InvalidOperationException. return Assert.ResultNotNull(this.Database.GetItem(this.ItemRootId), string.Concat(&q...

IsNotNull This is a very simple and popular method to use to check if an item is not null. It simply checks the object that is passed in to see if it is null. Assert.IsNotNull(database, type, "Name: {0}", item); IsNotNullOrEmpty This is the same as IsNotNull above, but works on strin...

ArgumentCondition This method checks to see if the argument specified is true. It also takes in the name of the argument that is logged if the condition fails. Assert.ArgumentCondition(pageIndex >= 0, "pageIndex", "Value must be greater than or equal to zero."); ArgumentN...

Checks to see if the passed Item is in Editing mode. If not, it throws an EditingNotAllowedException. Assert.IsEditing(Sitecore.Context.Item);

When writing a class with generics in java, it is possible to ensure that the type parameter is an enum. Since all enums extend the Enum class, the following syntax may be used. public class Holder<T extends Enum<T>> { public final T value; public Holder(T init) { t...