Tutorial by Examples: le

The following is a timer that fires at a fixed interval. It's timeout is defined by Period and it invokes a callback defined by Timerfcn upon timeout. t = timer; t.TasksToExecute = Inf; t.Period = 0.01; % timeout value in seconds t.TimerFcn = @(myTimerObj, thisEvent)disp('hello'); % timer callba...

Suppose you have a simple Customer model: class Customer(models.Model): first_name = models.CharField(max_length=255) last_name = models.CharField(max_length=255) is_premium = models.BooleanField(default=False) You register it in the Django admin and add search field by first_name...

class Foo { private string[] cities = new[] { "Paris", "London", "Berlin" }; public string this[int index] { get { return cities[index]; } set { cities[index] = value; } } } Usage...

Delegates can be used as typed function pointers: class FuncAsParameters { public void Run() { DoSomething(ErrorHandler1); DoSomething(ErrorHandler2); } public bool ErrorHandler1(string message) { Console.WriteLine(message); var shouldWeContinue = ... re...

If you want to calculate with BigDecimal you have to use the returned value because BigDecimal objects are immutable: BigDecimal a = new BigDecimal("42.23"); BigDecimal b = new BigDecimal("10.001"); a.add(b); // a will still be 42.23 BigDecimal c = a.add(b); // c will be ...

The Singleton pattern is a design pattern that restricts the instantiation of a class to one object. After the first object is created, it will return the reference to the same one whenever called for an object. var Singleton = (function () { // instance stores a reference to the Singlet...

Module Pattern The Module pattern is a creational and structural design pattern which provides a way of encapsulating private members while producing a public API. This is accomplished by creating an IIFE which allows us to define variables only available in its scope (through closure) while return...

To compare strings alphabetically, use localeCompare(). This returns a negative value if the reference string is lexicographically (alphabetically) before the compared string (the parameter), a positive value if it comes afterwards, and a value of 0 if they are equal. var a = "hello"; va...

This is an example of a function which returns a string. In the example, the function is called in a statement assigning a value to a variable. The value in this case is the return value of the function. function Get-Greeting{ "Hello World" } # Invoking the function $greeting ...

This example listens for input coming in over the serial connection, then repeats it back out the same connection. byte incomingBytes; void setup() { Serial.begin(9600); // Opens serial port, sets data rate to 9600 bps. } void loop() { // Send data only when you receive...

The base package parallel allows parallel computation through forking, sockets, and random-number generation. Detect the number of cores present on the localhost: parallel::detectCores(all.tests = FALSE, logical = TRUE) Create a cluster of the cores on the localhost: parallelCluster <- para...

If MsgBox("Click OK") = vbOK Then can be used in place of If MsgBox("Click OK") = 1 Then in order to improve readability. Use Object Browser to find available VB constants. View → Object Browser or F2 from VB Editor. Enter class to search View members available ...

Descriptive names and structure in your code help make comments unnecessary Dim ductWidth As Double Dim ductHeight As Double Dim ductArea As Double ductArea = ductWidth * ductHeight is better than Dim a, w, h a = w * h This is especially helpful when you are copying data from one ...

The .GetValueOrDefault() method returns a value even if the .HasValue property is false (unlike the Value property, which throws an exception). class Program { static void Main() { int? nullableExample = null; int result = nullableExample.GetValueOrDefault(); C...

C++11 C++11 introduces two new special member functions: the move constructor and the move assignment operator. For all the same reasons that you want to follow the Rule of Three in C++03, you usually want to follow the Rule of Five in C++11: If a class requires ONE of five special member functions...

C++11 We can combine the principles of the Rule of Five and RAII to get a much leaner interface: the Rule of Zero: any resource that needs to be managed should be in its own type. That type would have to follow the Rule of Five, but all users of that resource do not need to write any of the five sp...

const auto input = "Some people, when confronted with a problem, think \"I know, I'll use regular expressions.\""s; smatch sm; cout << input << endl; // If input ends in a quotation that contains a word that begins with "reg" and another word begining...

This code takes in various brace styles and converts them to One True Brace Style: const auto input = "if (KnR)\n\tfoo();\nif (spaces) {\n foo();\n}\nif (allman)\n{\n\tfoo();\n}\nif (horstmann)\n{\tfoo();\n}\nif (pico)\n{\tfoo(); }\nif (whitesmiths)\n\t{\n\tfoo();\n\t}\n"s; cout &lt...

A std::regex_token_iterator provides a tremendous tool for extracting elements of a Comma Separated Value file. Aside from the advantages of iteration, this iterator is also able to capture escaped commas where other methods struggle: const auto input = "please split,this,csv, ,line,\\,\n&quot...

When processing of captures has to be done iteratively a regex_iterator is a good choice. Dereferencing a regex_iterator returns a match_result. This is great for conditional captures or captures which have interdependence. Let's say that we want to tokenize some C++ code. Given: enum TOKENS { ...