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zip takes two lists and returns a list of corresponding pairs: zip [] _ = [] zip _ [] = [] zip (a:as) (b:bs) = (a,b) : zip as bs > zip [1,3,5] [2,4,6] > [(1,2),(3,4),(5,6)] Zipping two lists with a function: zipWith f [] _ = [] zipWith f _ [] =...

View loading In a test for a view controller you want sometimes to trigger the execution of loadView() or viewDidLoad(). This can be done by accessing the view. Let's say you have view controller instance in your test called sut (system under test), then the code would look like this: XCTAssertNot...

Some attributes are directly accessible as properties of the element (e.g. alt, href, id, title and value). document.querySelector("a").href = "#top"; Other attributes, including data-attributes can be set as follows: document.querySelector("a").setAttribute("...

To remove an attribute, including directly accessible properties document.querySelector("a").removeAttribute("title"); Data attributes can also be removed as follows (modern browsers): // remove "data-foo" attribute delete document.querySelector("a").dat...

This does not cover allocators. struct A {}; struct B { B()=default; B(B const&)=default; B(int){}; }; struct C { C()=delete; C(int) {}; C(C const&)=default; }; struct D { D( std::initializer_list<int> ) {}; D(D const&)=default; D()=default; }; std::variant<A,B> var_ab...

The original C standard had no intrinsic Boolean type, so bool, true and false had no inherent meaning and were often defined by programmers. Typically true would be defined as 1 and false would be defined as 0. C99 C99 adds the built-in type _Bool and the header <stdbool.h> which defines bo...

To make a jar, you need one or more class files. This should have a main method if it is to be run by a double click. For this example, we will use: import javax.swing.*; import java.awt.Container; public class HelloWorld { public static void main(String[] args) { JFrame f = ne...

Starting with the Support Library version 22.2.1, it's possible to show and hide a FloatingActionButton from scrolling behavior using a FloatingActionButton.Behavior sublclass that takes advantage of the show() and hide() methods. Note that this only works with a CoordinatorLayout in conjunction wi...

You can define a method to accept an arbitrary number of keyword arguments using the double splat (**) operator: def say(**args) puts args end say foo: "1", bar: "2" # {:foo=>"1", :bar=>"2"} The arguments are captured in a Hash. You can manip...

Unlike a parallel for-loop (parfor), which takes the iterations of a loop and distributes them among multiple threads, a single program, multiple data (spmd) statement takes a series of commands and distributes them to all the threads, so that each thread performs the command and stores the results....

Using Alternatives Many Linux distributions use the alternatives command for switching between different versions of a command. You can use this for switching between different versions of Java installed on a machine. In a command shell, set $JDK to the pathname of a newly installed JDK; e.g....

To remove all elements from a Map, use the .clear() method: map.clear(); Example: const map = new Map([[1, 2], [3, 4]]); console.log(map.size); // 2 map.clear(); console.log(map.size); // 0 console.log(map.get(1)); // undefined

To remove an element from a map use the .delete() method. map.delete(key); Example: const map = new Map([[1, 2], [3, 4]]); console.log(map.get(3)); // 4 map.delete(3); console.log(map.get(3)); // undefined This method returns true if the element existed and has been removed, otherwise fal...

Use .get(key) to get value by key and .set(key, value) to assign a value to a key. If the element with the specified key doesn't exist in the map, .get() returns undefined. .set() method returns the map object, so you can chain .set() calls. const map = new Map(); console.log(map.get(1)); // und...

Delegates are types that represent a reference to a method. They are used for passing methods as arguments to other methods. Delegates can hold static methods, instance methods, anonymous methods, or lambda expressions. class DelegateExample { public void Run() { //using class ...

Building project dependencies can sometimes be a tedious task. Instead of publishing a package version to NPM and installing the dependency to test the changes, use npm link. npm link creates a symlink so the latest code can be tested in a local environment. This makes testing global tools and proje...

This example shows how to render text along an arc. It includes how you can add functionality to the CanvasRenderingContext2D by extending its prototype. This examples is derived from the stackoverflow answer Circular Text. Example rendering Example code The example adds 3 new text renderi...

The Collections class provides a way to make a list unmodifiable: List<String> ls = new ArrayList<String>(); List<String> unmodifiableList = Collections.unmodifiableList(ls); If you want an unmodifiable list with one item you can use: List<String> unmodifiableList = Col...

Comparator.comparing(Person::getName) This creates a comparator for the class Person that uses this person name as the comparison source. Also it is possible to use method version to compare long, int and double. For example: Comparator.comparingInt(Person::getAge) Reversed order To create ...

CREATE TYPE dbo.Ids as TABLE ( Id int PRIMARY KEY )