Tutorial by Examples: w

This program uses the Windows API (WinAPI) to print "Hello World" into a message box. To include a dependency (like Windows in this case), add the uses block including a comma-separated list of units ending with an semicolon. program HelloWorld; uses Windows; begin MessageBox...

To document a function, it is often helpful to have an example script which uses your function. The publish function in Matlab can then be used to generate a help file with embedded pictures, code, links, etc. The syntax for documenting your code can be found here. The Function This function uses ...

Prerequisite: Installing Gradle Once you have Gradle installed, you can setup a new or existing project by running cd $PROJECT_DIR gradle init --type=java-library Note that there are other project types like Scala you can get started with, but we'll use Java for this example. You will end up ...

Folds are (higher-order) functions used with sequences of elements. They collapse seq<'a> into 'b where 'b is any type (possibly still 'a). This is a bit abstract so lets get into concrete practical examples. Calculating the sum of all numbers In this example, 'a is an int. We have a list of...

type Person = { Age : int PassedDriversTest : bool } let someone = { Age = 19; PassedDriversTest = true } match someone.PassedDriversTest with | true when someone.Age >= 16 -> printfn "congrats" | true -> printfn "wait until you are 16" | false -> p...

>>> code = """for i in range(5):\n print('Hello world!')""" >>> exec(code) Hello world! Hello world! Hello world! Hello world! Hello world!

>>> expression = '5 + 3 * a' >>> a = 5 >>> result = eval(expression) >>> result 20

>>> variables = {'a': 6, 'b': 7} >>> eval('a * b', globals=variables) 42 As a plus, with this the code cannot accidentally refer to the names defined outside: >>> eval('variables') {'a': 6, 'b': 7} >>> eval('variables', globals=variables) Traceback (most ...

Static gives a method or variable storage that is not allocated for each instance of the class. Rather, the static variable is shared among all class members. Incidentally, trying to treat the static variable like a member of the class instance will result in a warning: public class Apple { pu...

It is possible to create a QtQuick view directly from C++ and to expose to QML C++ defined properties. In the code below the C++ program creates a QtQuick view and exposes to QML the height and width of the view as properties. main.cpp #include <QApplication> #include <QQmlContext> #...

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...

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): ...

Record syntax can be used with newtype with the restriction that there is exactly one constructor with exactly one field. The benefit here is the automatic creation of a function to unwrap the newtype. These fields are often named starting with run for monads, get for monoids, and un for other typ...

Differences in subsetting syntax A data.table is one of several two-dimensional data structures available in R, besides data.frame, matrix and (2D) array. All of these classes use a very similar but not identical syntax for subsetting, the A[rows, cols] schema. Consider the following data stored i...

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...

With ASP.NET Core 1.0, the MVC and Web API framework have been merged into one framework called ASP.NET Core MVC. This is a good thing, since MVC and Web API share a lot of functionality, yet there always were subtle differences and code duplication. However, merging these two into framework one ...

F|forbidden Similar to Deny, this flag forces the server to immediately return a 403 Forbidden status code to the requesting browser or client for the request. Example: Deny access to requests that end with exe: RewriteRule .exe$ - [F] G|gone If a requested resource was available in the past,...

Sometimes you want to destructure key under a map which might not be present in the map, but you want a default value for the destructured value. You can do that this way: (def my-map {:a 3 :b 4}) (let [{a :a b :b :keys [c d] :or {a 1 c 2}} my-map] (println ...