Tutorial by Examples: f

The <footer> element contains the footer part of the page. Here is an example for <footer> element that contain p paragraph tag. <footer> <p>All rights reserved</p> </footer>

Multiton can be used as a container for singletons. This is Multiton implementation is a combination of Singleton and Pool patterns. This is an example of how common Multiton abstract Pool class can be created: abstract class MultitonPoolAbstract { /** * @var array */ protec...

This pattern can be used to contain a registered Pools of Singletons, each distinguished by unique ID: abstract class MultitonRegistryAbstract { /** * @var array */ protected static $instances = []; /** * @param string $id */ final protected function ...

In bash, you have to quote arguments in order to preserve white space: # bash function print_first_argument { echo "$1" } argument="has white space" print_first_argument "$argument" In Zsh, you don't need the quotes, because of different evaluation orde...

Passing a 2d array to a functions seems simple and obvious and we happily write: #include <stdio.h> #include <stdlib.h> #define ROWS 3 #define COLS 2 void fun1(int **, int, int); int main() { int array_2D[ROWS][COLS] = { {1, 2}, {3, 4}, {5, 6} }; int n = ROWS; int m...

If you want to add a UIImageView to the center of the screen with width and height of 100 pixel, you need to set center x constraint and center y constraint to the superview from the UIImageView and width, height constraint to the UIIMageView. Here is the code. There is way to do this in storyboard ...

A NullReferenceException is thrown when you try to access a non-static member (property, method, field or event) of a reference object but it is null. Car myFirstCar = new Car(); Car mySecondCar = null; Color myFirstColor = myFirstCar.Color; // No problem as myFirstCar exists / is not null Color...

Xamarin is becoming more and more popular - it is hard to decide when to use Xamarin.Forms and when Xamarin.Platform (so Xamarin.iOS and Xamarin.Android). First of all you should know for what kind of applications you can use Xamarin.Forms: Prototypes - to visualize how your application will l...

You can execute SQL query as different user using AS USER = 'name of database user' EXEC(N'SELECT * FROM product') AS USER = 'dbo' SQL query will be executed under dbo database user. All permission checks applicable to dbo user will be checked on SQL query.

Django's built-in User model is not always appropiate for some kinds of projects. On some sites it might make more sense to use an email address instead of a username for instance. You can override the default User model adding your customized User model to the AUTH_USER_MODEL setting, in your proj...

Your code will not work in projects where you reference the User model (and where the AUTH_USER_MODEL setting has been changed) directly. For example: if you want to create Post model for a blog with a customized User model, you should specify the custom User model like this: from django.conf impo...

SQL Server 2012 The OFFSET FETCH clause implements pagination in a more concise manner. With it, it's possible to skip N1 rows (specified in OFFSET) and return the next N2 rows (specified in FETCH): SELECT * FROM sys.objects ORDER BY object_id OFFSET 40 ROWS FETCH NEXT 10 ROWS ONLY The ORDER...

Writing a gzipped file To write a gzipped file, use the module IO::Compress::Gzip and create a filehandle by creating a new instance of IO::Compress::Gzip for the desired output file: use strict; use warnings; use open qw( :encoding(UTF-8) :std ); # Make UTF-8 default encoding use IO::Compres...

Generating the minimum number of operations to transform one tree into another have a complexity in the order of O(n^3) where n is the number of nodes in the tree. React relies on two assumptions to solve this problem in a linear time - O(n) Two components of the same class will generate sim...

There are two equivalent ways to calculate the amount of time unit between two LocalTime: (1) through until(Temporal, TemporalUnit) method and through (2) TemporalUnit.between(Temporal, Temporal). import java.time.LocalTime; import java.time.temporal.ChronoUnit; public class AmountOfTime { ...

This method doesn't require initialization of the tracker, which is handy if the state should be changed outside of the site context (for example in the shell). var stateManager = AutomationStateManager.Create(contact); automationStateManager.MoveToEngagementState(stateItem.ParentID, stateId); st...

Sometimes, it's better to have only three options style="@android:style/TextAppearance.Small" style="@android:style/TextAppearance.Medium" style="@android:style/TextAppearance.Large" Use small and large to differentiate from normal screen size. <TextView ...

Specifies that the query is optimized for fast retrieval of the first number_rows. This is a nonnegative integer. After the first number_rows are returned, the query continues execution and produces its full result set. select OrderID, AVG(Quantity) from Sales.OrderLines group by OrderID OPTION ...

JSON_MODIFY function uses JSON text as input parameter, and modifies a value on the specified path using third argument: declare @json nvarchar(4000) = N'{"Id":1,"Name":"Toy Car","Price":34.99}' set @json = JSON_MODIFY(@json, '$.Price', 39.99) print @json -...

You can generate JSON object using standard SELECT query with FOR JSON clause and insert it into JSON text as third parameter: declare @json nvarchar(4000) = N'{"Id":17,"Name":"WWI"}' set @json = JSON_MODIFY(@json, '$.tables', (select name fr...