Tutorial by Examples: er

Type type = obj.GetType(); //To restrict return properties. If all properties are required don't provide flag. BindingFlags flags = BindingFlags.Public | BindingFlags.Instance; PropertyInfo[] properties = type.GetProperties(flags); foreach (PropertyInfo property in properties) { Console...

You can add an interpreter directive (shebang) to your script. Create a file called hello_world.rb which contains: #!/usr/bin/env ruby puts 'Hello World!' Give the script executable permissions. Here's how to do that in Unix: $ chmod u+x hello_world.rb Now you do not need to call the Ru...

let x = true match x with | true -> printfn "x is true" yields a warning C:\Program Files (x86)\Microsoft VS Code\Untitled-1(2,7): warning FS0025: Incomplete pattern matches on this expression. For example, the value 'false' may indicate a case not covered by the pattern(s). ...

Returns a string that represents the unqualified name of a variable, type, or member. int counter = 10; nameof(counter); // Returns "counter" Client client = new Client(); nameof(client.Address.PostalCode)); // Returns "PostalCode" The nameof operator was introduced in C# ...

If you want to mock AR that doesn't try to connect to database you can do it in the following way (if using PHPUnit): $post = $this->getMockBuilder('\app\model\Post') ->setMethods(['save', 'attributes']) ->getMock(); $post->method('save')->willReturn(true); $post->meth...

The Master directive specifies a page file as being the mater page. The basic syntax of sample MasterPage directive is: <%@ MasterPage Language="C#" AutoEventWireup="true" CodeFile="SiteMater.master.cs" Inherits="SiteMaster" %>

The MasterType directive assigns a class name to the Master property of a page, to make it strongly typed. The basic syntax of MasterType directive is: <%@ MasterType attribute="value"[attribute="value" ...] %>

This example show how you can check if a service already exists (i.e., is installed on the machine) or not. This code requires only the lowest privileges necessary, so each process can perform the check, no matter what level of security it is running at. #define UNICODE #define _UNICODE #include ...

In Visual studio go to Tools > Extensions and updates... In the window that opens go to online Select Visual Studio Gallery You can search for an extension on the search box at the upper right corner Select the extension you want to add Click on download. Once download is complete, click...

int x = 5 / 0; // Undefined behavior Division by 0 is mathematically undefined, and as such it makes sense that this is undefined behavior. However: float x = 5.0f / 0.0f; // x is +infinity Most implementation implement IEEE-754, which defines floating point division by zero to return N...

int x = INT_MAX + 1; // x can be anything -> Undefined behavior If during the evaluation of an expression, the result is not mathematically defined or not in the range of representable values for its type, the behavior is undefined. (C++11 Standard paragraph 5/4) This is one of the mo...

By default, Django renders ForeignKey fields as a <select> input. This can cause pages to be load really slowly if you have thousands or tens of thousand entries in the referenced table. And even if you have only hundreds of entries, it is quite uncomfortable to look for a particular entry amo...

Using threading & queue: from socket import socket, AF_INET, SOCK_STREAM from threading import Thread from queue import Queue def echo_server(addr, nworkers): print('Echo server running at', addr) # Launch the client workers q = Queue() for n in range(nworkers): ...

Interfaces may have variant type parameters. interface IEnumerable<out T> { // ... } interface IComparer<in T> { // ... } but classes and structures may not class BadClass<in T1, out T2> // not allowed { } struct BadStruct<in T1, out T2> // not allo...

In a non-strict-mode scope, when a variable is assigned without being initialized with the var, const or the let keyword, it is automatically declared in the global scope: a = 12; console.log(a); // 12 In strict mode however, any access to an undeclared variable will throw a reference error: &...

If you have a string that contains Python literals, such as strings, floats etc, you can use ast.literal_eval to evaluate its value instead of eval. This has the added feature of allowing only certain syntax. >>> import ast >>> code = """(1, 2, {'foo': 'bar'})&quot...

It is not possible to use eval or exec to execute code from untrusted user securely. Even ast.literal_eval is prone to crashes in the parser. It is sometimes possible to guard against malicious code execution, but it doesn't exclude the possibility of outright crashes in the parser or the tokenizer....

You can select elements with different selectors : by tag : "div" by class : ".class" by id : "#id" by attribute : "[color=blue]" multiple selectors (OR): "div1, div2, class1" multiple selectors (AND): "div1 div2 class1"

This will give current system version. Objective-C NSString *version = [[UIDevice currentDevice] systemVersion] Swift let version = UIDevice.currentDevice().systemVersion Swift 3 let version = UIDevice.current.systemVersion

<div class="navbar navbar-inverse navbar-fixed-top"> <div class="container"> <div class="navbar-header"> <button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".n...