Tutorial by Examples: nd

In Haskell, data types can have arguments just like functions. Take the Maybe type for example. Maybe is a very useful type which allows us to represent the idea of failure, or the possiblity thereof. In other words, if there is a possibility that a computation will fail, we use the Maybe type ther...

To support a given application, you often create a new role and database to match. The shell commands to run would be these: $ createuser -P blogger Enter password for the new role: ******** Enter it again: ******** $ createdb -O blogger blogger This assumes that pg_hba.conf has been prope...

If you use an index that is sorted the way you would retrieve it, the SELECT statement would not do additional sorting when in retrieval. CREATE INDEX ix_scoreboard_score ON scoreboard (score DESC); When you execute the query SELECT * FROM scoreboard ORDER BY score DESC; The database system ...

Layout Unity basic editor will look like below. Basic functionalities of some default windows/tabs are described in the image. Linux Layout There is a little difference in menu layout of linux version, like the screenshot below, Basic Usage Create an empty GameObject by right clicking in th...

Whenever a Python script is invoked from the command line, the user may supply additional command line arguments which will be passed on to the script. These arguments will be available to the programmer from the system variable sys.argv ("argv" is a traditional name used in most programmi...

Good unit tests are independent, but code often has dependencies. We use various kinds of test doubles to remove the dependencies for testing. One of the simplest test doubles is a stub. This is a function with a hard-coded return value called in place of the real-world dependency. // Test that ...

If you are able to download an update of Android Studio, but after it restarts nothing happens, check out the following example: After the patch was downloaded and Android Studio closed, open the terminal Go to your android studio folder, e.g. cd ~/android-studio Go to bin subfolder: cd bin ...

To use Leaflet, load its stylesheet and JavaScript file to your page: <link rel="stylesheet" href="/css/leaflet.css" /> <script src="/js/leaflet.js"></script> These resources can be downloaded from a variety of locations such as Leaflet's homepage...

// *** Find movies except given ids *** NSPredicate *filterByNotInIds = [NSPredicate predicateWithFormat:@"NOT (self.id IN %@)",@[@"7CDF6D22-8D36-49C2-84FE-E31EECCECB79", @"7CDF6D22-8D36-49C2-84FE-E31EECCECB76"]]; NSLog(@"Filter movies except given Ids : %@"...

// *** Find all the objects which is of type movie, Both the syntax are valid *** NSPredicate *filterByMovieType = [NSPredicate predicateWithFormat:@"self.isMovie = %@",@1]; // OR //NSPredicate *filterByMovieType = [NSPredicate predicateWithFormat:@"self.isMovie = %@",[NSNumbe...

// *** Find Distinct object ids of array *** NSLog(@"Distinct id : %@",[array valueForKeyPath:@"@distinctUnionOfObjects.id"]);

// *** Find movies with specific ids *** NSPredicate *filterByIds = [NSPredicate predicateWithFormat:@"self.id IN %@",@[@"7CDF6D22-8D36-49C2-84FE-E31EECCECB79", @"7CDF6D22-8D36-49C2-84FE-E31EECCECB76"]]; NSLog(@"Filter By Ids : %@",[array filteredArrayUsingP...

It is usually not a good idea to mix signed and unsigned integers in arithmetic operations. For example, what will be output of following example? #include <stdio.h> int main(void) { unsigned int a = 1000; signed int b = -1; if (a > b) puts("a is more than b&quot...

The simplest way to concatenate list1 and list2: merged = list1 + list2 zip returns a list of tuples, where the i-th tuple contains the i-th element from each of the argument sequences or iterables: alist = ['a1', 'a2', 'a3'] blist = ['b1', 'b2', 'b3'] for a, b in zip(alist, blist):...

prepend() - Insert content, specified by the parameter, to the beginning of each element in the set of matched elements. 1. prepend( content [, content ] ) // with html string jQuery('#parent').prepend('<span>child</span>'); // or you can use jQuery object jQuery('#parent').prepend(...

The following example shows how you can deserialize a JSON string containing into an Object (i.e. into an instance of a class). using System; using System.Collections.Generic; using Newtonsoft.Json; public class Program { public class Employee { public s...

$customer = Customer::findOne(10); or $customer = Customer::find()->where(['id' => 10])->one(); or $customer = Customer::find()->select('name,age')->where(['id' => 10])->one(); or $customer = Customer::findOne(['age' => 30, 'status' => 1]); or $customer = C...

Creating a Custom Element with bindable properties is a snap. If you want to create an element that accepts one or more values which the plugin can use, the @bindable decorator and syntax is what you are looking for. Below, we are creating a custom element that accepts an array of fruits and displa...

In the following, we are creating an example of an Aurelia Custom Element which will allow you to display Youtube videos via their video ID. An Aurelia Custom Element can be defined in two different ways: the first one is by creating a viewmodel and accompanying view, the second one is by just cre...

Installation npm install -D webpack typescript ts-loader webpack.config.js module.exports = { entry: { app: ['./src/'], }, output: { path: __dirname, filename: './dist/[name].js', }, resolve: { extensions: ['', '.js', '.ts'], }, module: { loaders: [...