Tutorial by Examples: d

sort command is used to sort a list of lines. Input from a file sort file.txt Input from a command You can sort any output command. In the example a list of file following a pattern. find * -name pattern | sort

Django Admin comes with some Models registerd by default. There a some occasions where you might want to remove a Model from the admin pages. This is done in the admin submodule. If your app wass created using manage.py startapp, the admin.py file should already lay in your app module. Otherwise cr...

Even if the result type of the query isn’t an entity type, if the result contains entity types they will still be tracked by default Example : In the following query, which returns an anonymous type, the instances of Book in the result set will be tracked using (var context = new BookC...

Sometimes we want to give extra information to our user with colors (for example red means something wrong has happened) We can change toast message background color using setting a color filter to the view which our toast give us (here I use a ColorMatrixColorFilter): Toast t = Toast.MakeText(con...

Every Keychain Item is most often represented as a CFDictionary. You can, however, simply use NSDictionary in Objective-C and take advantage of bridging, or in Swift you may use Dictionary and explicitly cast to CFDictionary. You could construct a password with the following dictionary: Swift var...

To construct a query, we need to represent it as a CFDictionary. You may also use NSDictionary in Objective-C or Dictionary in Swift and cast to CFDictionary. We need a class key: Swift var dict = [String : AnyObject]() dict[kSecClass as String] = kSecClassGenericPassword Next, we can specify...

As usual, we first need a CFDictionary to represent the item we want to update. This must contain all of the old values for the item, including the old private data. Then it takes a CFDictionary of any attributes or the data itself that you would like to change. So first, let's construct a class ke...

Add this dependency to your project POM: <dependency> <groupId>com.typesafe.akka</groupId> <artifactId>akka-actor_2.11</artifactId> <version>2.4.4</version> </dependency> Create an Actor public class HelloWorldActor ext...

We need only one thing in order to delete an item from the Keychain: a CFDictionary with attributes describing the items to be deleted. Any items that match the query dictionary will be deleted permanently, so if you are only intending to delete a single item be sure to be specific with your query. ...

The JAR, WAR and EAR files types are fundamentally ZIP files with a "manifest" file and (for WAR and EAR files) a particular internal directory / file structure. The recommended way to create these files is to use a Java-specific build tool which "understands" the requirements f...

from PIL import Image im = Image.open("Image.bmp")

The Oracle Java Tutorials summarize Web Start as follows: Java Web Start software provides the power to launch full-featured applications with a single click. Users can download and launch applications, such as a complete spreadsheet program or an Internet chat client, without going through lengt...

Functions are an important part of Julia programming. They can be defined directly within modules, in which case the functions are referred to as top-level. But functions can also be defined within other functions. Such functions are called "closures". Closures capture the variables in th...

If the ORDER BY clause is specified in your update SQL statement, the rows are updated in the order that is specified. If LIMIT clause is specified in your SQL statement, that places a limit on the number of rows that can be updated. There is no limit, if LIMIT clause not specified. ORDER BY and L...

In multiple table UPDATE, it updates rows in each specified tables that satisfy the conditions. Each matching row is updated once, even if it matches the conditions multiple times. In multiple table UPDATE, ORDER BY and LIMIT cannot be used. Syntax for multi table UPDATE is, UPDATE [LOW_PRIORITY]...

By default Controllers, ViewComponents and TagHelpers aren't registered and resolved via the dependency injection container. This results in the inability to do i.e. property injection when using a 3rd party Inversion of Control (IoC) container like AutoFac. In order to make ASP.NET Core MVC resolv...

dispatch_group_t preapreWaitingGroup = dispatch_group_create(); dispatch_group_enter(preapreWaitingGroup); [self doAsynchronousTaskWithComplete:^(id someResults, NSError *error) { // Notify that this task has been completed. dispatch_group_leave(preapreWaitingGroup); }] dispatch...

Difference from PHP Array PHP's default Array type is actually implemented as ordered hash maps, which allow us to create arrays that consist of key/value pairs where values can be of any type and keys can be either numbers or strings. This is not traditionally how arrays are created, however. S...

Prerequisites Have a strong grasp of a programming language such as Python, C, C++, Ruby, or any of the other languages out there. Have your favorite code editor or IDE installed (one such example is VSCode) Stay motivated. Constructing a compiler is not easy, so keep pushing; it's worth the ef...

In Google Chrome's developer tools "Elements", you can see that the selected line shows ==$0 that is the DOM node index(as shown below): $0 returns the most recently selected element or JavaScript object, $1 returns the second most recently selected one, and so on. This is useful ...