Tutorial by Examples: 4

Value type - short, int, long (signed 16 bit, 32 bit, 64 bit integers)

// assigning a signed short to its minimum value short s = -32768; // assigning a signed short to its maximum value short s = 32767; // assigning a signed int to its minimum value int i = -2147483648; // assigning a signed int to its maximum value int i = 2147483647; // assigning a s...

C# Language • Built-in Types

Value type - ushort, uint, ulong (unsigned 16 bit, 32 bit, 64 bit integers)

// assigning an unsigned short to its minimum value ushort s = 0; // assigning an unsigned short to its maximum value ushort s = 65535; // assigning an unsigned int to its minimum value uint i = 0; // assigning an unsigned int to its maximum value uint i = 4294967295; // assigning an...

C# Language • Built-in Types

Wildcard Channel Group Manage Grant - Java SDK v4

When it comes to adding/removing channels to/from your channel groups, you need to have must have the manage permission for those channel groups. But you should never grant clients the permission to manage the channel groups that they will subscribe to. If they did, then they could add any channel t...

PubNub • Access Manager

Creating a TypedArray from a Base64 string

var data = 'iVBORw0KGgoAAAANSUhEUgAAAAUAAAAFCAYAAACN' + 'byblAAAAHElEQVQI12P4//8/w38GIAXDIBKE0DHx' + 'gljNBAAO9TXL0Y4OHwAAAABJRU5ErkJggg=='; var characters = atob(data); var array = new Uint8Array(characters.length); for (var i = 0; i < characters.length; i++) { array[i] ...

JavaScript • Binary Data

Base64 Encoding / Decoding

Occasionally you will find the need to encode binary data as a base64-encoded string. For this we can use the DatatypeConverter class from the javax.xml.bind package: import javax.xml.bind.DatatypeConverter; import java.util.Arrays; // arbitrary binary data specified as a byte array byte[] bi...

Java Language • Converting to and from Strings

Different Kinds of Streams #4 - iterate an array, map the values, calculate the average

// Java: Arrays.stream(new int[] {1, 2, 3}) .map(n -> 2 * n + 1) .average() .ifPresent(System.out::println); // 5.0 // Kotlin: arrayOf(1,2,3).map { 2 * it + 1}.average().apply(::println)

Kotlin • Java 8 Stream Equivalents

Error code 1064: Syntax error

select LastName, FirstName, from Person Returns message: Error Code: 1064. You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'from Person' at line 2. Getting a "1064 error" message from MySQL mean...

MySQL • Error codes

HTML 4.01 Doctypes

The HTML 4.01 specification provides several different types of doctypes that allow different types of elements to be specified within the document. HTML 4.01 Strict <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> Includes all...

HTML • Doctypes

Creating an enum (Python 2.4 through 3.3)

Enums have been backported from Python 3.4 to Python 2.4 through Python 3.3. You can get this the enum34 backport from PyPI. pip install enum34 Creation of an enum is identical to how it works in Python 3.4+ from enum import Enum class Color(Enum): red = 1 green = 2 blue = 3 ...

Python Language • Enum

Return a 404 response

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...

symfony2 • Routing

Installation of PyQt4

Suggested Install Method Windows: Download and run the binary setup file. Linux(Debian): Run this command in your command line: $ apt-get install python-qt4 pyqt4-dev-tools qt4-designer OS X : Run this command in your command line: $ brew install pyqt Install Manually You can also downloa...

pyqt • Getting started with pyqt

Web.config setup to target 4.5 for correct async behaviour.

The web.config system.web.httpRuntime must target 4.5 to ensure the thread will renter the request context before resuming your async method. <httpRuntime targetFramework="4.5" /> Async and await have undefined behavior on ASP.NET prior to 4.5. Async / await will resume on an arb...

C# Language • Async-Await

4. Creating the Symfony Application

Once the Symfony Installer is available, create your first Symfony application with the new command: # Linux, Mac OS X $ symfony new my_project_name # Windows c:\> cd projects/ c:\projects\> php symfony new my_project_name This command can be run from anywhere, not necessarily from t...

symfony3 • Getting started with symfony3

Error handling of specific HTTP response codes (such as 404 Not Found)

using System.Net; ... string serverResponse; try { // Call a method that performs an HTTP request (per the above examples). serverResponse = PerformHttpRequest(); } catch (WebException ex) { if (ex.Status == WebExceptionStatus.ProtocolError) { HttpWebResponse...

C# Language • Performing HTTP requests

ConcurrentDictionary (from .NET 4.0)

Represents a thread-safe collection of key/value pairs that can be accessed by multiple threads concurrently. Creating an instance Creating an instance works pretty much the same way as with Dictionary<TKey, TValue>, e.g.: var dict = new ConcurrentDictionary<int, string>(); Ad...

.NET Framework • Dictionaries

404 when record not found

Rescue from record not found error instead of showing an exception or white page: class ApplicationController < ActionController::Base # ... your other stuff here rescue_from ActiveRecord::RecordNotFound do |exception| redirect_to root_path, 404, alert: 'Record not found' en...

Ruby on Rails • ActionController

64-bit registers

AMD is a processor manufacturer that had licensed the design of the 80386 from Intel to produce compatible - but competing - versions. They made internal changes to the design to improve throughput or other enhancements to the design, while still being able to execute the same programs. To one-up I...

Intel x86 Assembly Language & Microarchitecture • Register Fundamentals

Encoding and decoding a string using NSData Base64

Encoding //Create a Base64 Encoded NSString Object NSData *nsdata = [@"iOS Developer Tips encoded in Base64" dataUsingEncoding:NSUTF8StringEncoding]; // Get NSString from NSData object in Base64 NSString *base64Encoded = [nsdata base64EncodedStringWithOptions:0]; // Print the B...

Objective-C Language • NSData

foldl/4

A fold (from the left) is a higher-order relation between: a predicate with 3 arguments a list of elements an initial state a final state, which is the result of applying the predicate to successive elements while carrying through intermediate states. For example: Use foldl/4 to express the...

Prolog Language • Higher-Order Programming

Installing Elasticsearch on Ubuntu 14.04

Prerequisites In order to run Elasticsearch, a Java Runtime Environment (JRE) is required on the machine. Elasticsearch requires Java 7 or higher and recommends Oracle JDK version 1.8.0_73. Install Oracle Java 8 sudo add-apt-repository -y ppa:webupd8team/java sudo apt-get update echo "or...

Elasticsearch • Getting started with Elasticsearch