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The implementation of INotifyPropertyChange can be error-prone, as the interface requires specifying property name as a string. In order to make the implementation more robust, an attribute CallerMemberName can be used. class C : INotifyPropertyChanged { // backing field int offset; ...

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#include <iostream> long double operator"" _km(long double val) { return val * 1000.0; } long double operator"" _mi(long double val) { return val * 1609.344; } int main() { std::cout << "3 km = " << 3.0_km << " m...

Batch execution using java.sql.PreparedStatement allows you to execute a single DML statement with multiple sets of values for its parameters. This example demonstrates how to prepare an insert statement and use it to insert multiple rows in a batch. Connection connection = ...; // obtained earl...

Batch execution using java.sql.Statement allows you to execute multiple DML statements (update, insert, delete) at once. This is achieved by creating a single statement object, adding the statements to execute, and then execute the batch as one. Connection connection = ...; // obtained earlier c...

Compare the definition of Free to that of Fix: data Free f a = Return a | Free (f (Free f a)) newtype Fix f = Fix { unFix :: f (Fix f) } In particular, compare the type of the Free constructor with the type of the Fix constructor. Free layers up a functor just like Fix, except ...

options = { "x": ["a", "b"], "y": [10, 20, 30] } Given a dictionary such as the one shown above, where there is a list representing a set of values to explore for the corresponding key. Suppose you want to explore "x"="a" w...

<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"> <rect x="10" y="10" width="50" height="100" stroke="black" stroke-width="5" fill="none" /> </svg> R...

The width and height attributes designate the dimensions of the rectangle. These values are in pixels by default The fill value sets the color for the rectangle. If no value for fill is specified, black is used by default <svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="h...

If you use a dictionary as an iterator (e.g. in a for statement), it traverses the keys of the dictionary. For example: d = {'a': 1, 'b': 2, 'c':3} for key in d: print(key, d[key]) # c 3 # b 2 # a 1 The same is true when used in a comprehension print([key for key in d]) # ['c', 'b', '...

Detailed instructions on launching an EC2 instance.

Throughout this example it is assumed that the 'root' object that is being serialized to JSON is an instance of the following class : public class MyJson { }   Example 1 : An example of an instance of MyJson, as is: {} i.e. since the class has no fields, only curly brackets are serialized...

If you are working with vectors or lines you will at some stage want to get the direction of a vector, or line. Or the direction from a point to another point. Math.atan(yComponent, xComponent) return the angle in radius within the range of -Math.PI to Math.PI (-180 to 180 deg) Direction of a vect...

If you have a vector in polar form (direction & distance) you will want to convert it to a cartesian vector with a x and y component. For referance the screen coordinate system has directions as 0 deg points from left to right, 90 (PI/2) point down the screen, and so on in a clock wise direction...

Math.sin and Math.cos are cyclic with a period of 2*PI radians (360 deg) they output a wave with an amplitude of 2 in the range -1 to 1. Graph of sine and cosine function: (courtesy Wikipedia) They are both very handy for many types of periodic calculations, from creating sound waves, to animati...

In XAML: <RadioButton IsChecked="{Binding EntityValue, Mode=TwoWay, Converter={StaticResource StringToIsCheckedConverter}, ConverterParameter=Male}" Content="Male"/> <RadioButton IsChecked="{Bindi...

public Result sayHello() { JsonNode json = request().body().asJson(); if(json == null) { return badRequest("Expecting Json data"); } else { String name = json.findPath("name").textValue(); if(name == null) { return badRequest...

@BodyParser.Of(BodyParser.Json.class) public Result sayHello() { JsonNode json = request().body().asJson(); String name = json.findPath("name").textValue(); if(name == null) { return badRequest("Missing parameter [name]"); } else { return ok...

A string can be used as a separator to join a list of strings together into a single string using the join() method. For example you can create a string where each element in a list is separated by a space. >>> " ".join(["once","upon","a","tim...

Python's string module provides constants for string related operations. To use them, import the string module: >>> import string string.ascii_letters: Concatenation of ascii_lowercase and ascii_uppercase: >>> string.ascii_letters 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQ...