Tutorial by Examples: od

There are three built-in REPL modes in Julia: the Julia mode, the help mode, and the shell mode. The Help Mode The Julia REPL comes with a built-in help system. Press ? at the julia> prompt to access the help?> prompt. At the help prompt, type the name of some function or type to get help f...

We have a tree data type like this: data Tree a = Tree a [Tree a] deriving Show And we wish to write a function that assigns a number to each node of the tree, from an incrementing counter: tag :: Tree a -> Tree (a, Int) The long way First we'll do it the long way around, since it illust...

Add the following directive before using any other mod_rewrite directive (RewriteRule, RewriteCond, RewriteBase or RewriteMap). RewriteEngine on By default the engine is turned off. mod_rewrite directives found while the engine is turned off are ignored. Enable it from within the virtual host co...

Important: Using the dynamic configuration files (.htaccess) is a big performance hit. When you have access to the static configuration file (httpd.conf or something similar) you should use that instead. In the static configuration file, allow dynamic configuration files to override "Filei...

In this exemple, we want to execute code which is stored in a string format. # the string str <- "1+1" # A string is not an expression. is.expression(str) [1] FALSE eval(str) [1] "1+1" # parse convert string into expressions parsed.str <- parse(text="1+1...

A module is a collection of related reusable functions (or cmdlets) that can easily be distributed to other PowerShell users and used in multiple scripts or directly in the console. A module is usually saved in it's own directory and consists of: One or more code files with the .psm1 file extensi...

extension String { func matchesPattern(pattern: String) -> Bool { do { let regex = try NSRegularExpression(pattern: pattern, options: NSRegularExpressionOptions(rawValue: 0)) let range: NSRange = NSMakeRange(...

In the old fashion way for collection null check List<Object> someObjects = methodGetList(); for (Object obj : someObjects) { if (obj == null) { continue; } doSomething(obj); } With the Objects.nonNull method and Java8 Stream API, we can do the above in this way: ...

The NotifyPropertyChangedBaseclass below defines a generic Set method that can be called from any derived type. public class NotifyPropertyChangedBase : INotifyPropertyChanged { protected void RaisePropertyChanged([CallerMemberName] string propertyName = null) => PropertyChanged?.Invo...

Consider the following partial example: import com.example.somelib.*; import com.acme.otherlib.*; public class Test { private Context x = new Context(); // from com.example.somelib ... } Suppose that when when you first developed the code against version 1.0 of somelib and versi...

Major mode Emacs can adapt its behaviour to the specific type of text edited in a buffer. The set of specific Emacs customizations for a particular type of text is called a "major mode". Each buffer has exactly one major mode depending on its content type. Major modes can change the mean...

JAXB can be used to generate classes from an model defined in XSD. It will then be possible to read XML document made against this XSD directly as java instances and inversly save these instances as XML document. Take the following XSD saved in a file named SimpleModel.xsd <?xml version="...

The Factory method pattern is a creational pattern that abstracts away the instantiation logic of an object in order to decouple the client code from it. When a factory method belongs to a class that is an implementation of another factory pattern such as Abstract factory then it is usually more ap...

Identify the item that is to be deleted and delete it: Invoke-RestMethod -Method Delete -Uri "http://jsonplaceholder.typicode.com/posts/1"

These are the available editions of SQL Server, as told by the Editions Matrix: Express: Entry-level free database. Includes core-RDBMS functionality. Limited to 10G of disk size. Ideal for development and testing. Standard Edition: Standard Licensed edition. Includes core functionality and Busi...

Draper automatically matches up models with their decorators by convention. # app/decorators/user_decorator.rb class UserDecorator < Draper::Decorator def full_name "#{object.first_name} #{object.last_name}" end def created_at Time.use_zone(h.current_user.timezone...

trait Speak { fn speak(&self) -> String { String::from("Hi.") } } The method will be called by default except if it's overwritten in the impl block. struct Human; struct Cat; impl Speak for Human {} impl Speak for Cat { fn speak(&self) -> S...

The following command backs up the 'Users' database to 'D:\DB_Backup' file. Its better to not give an extension. BACKUP DATABASE Users TO DISK = 'D:\DB_Backup'

The find function First let's take a look at the string.find function in general: The function string.find (s, substr [, init [, plain]]) returns the start and end index of a substring if found, and nil otherwise, starting at the index init if it is provided (defaults to 1). ("Hello, I am a ...

public static async Task PostAsync(this Uri uri, object value) { var content = new ObjectContext(value.GetType(), value, new JsonMediaTypeFormatter()); using (var client = new HttpClient()) { return await client.PostAsync(uri, content); } } . . . var uri = new ...