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If I wanted to find out the sum of numbers from 1 to n where n is a natural number, I can do 1 + 2 + 3 + 4 + ... + (several hours later) + n. Alternatively, I could write a for loop: n = 0 for i in range (1, n+1): n += i Or I could use a technique known as recursion: def recursion(n): ...

App.xaml.cs file (App.xaml file is default, so skipped) using Xamrin.Forms namespace NavigationApp { public partial class App : Application { public static INavigation GlobalNavigation { get; private set; } public App() { InitializeComponent()...

You can perform redirection in Rails routes as follows: 4.0 get '/stories', to: redirect('/posts') 4.0 match "/abc" => redirect("http://example.com/abc") You can also redirect all unknown routes to a given path: 4.0 match '*path' => redirect('/'), via: :get ...

// get some data from stackoverflow fetch("https://api.stackexchange.com/2.2/questions/featured?order=desc&sort=activity&site=stackoverflow") .then(resp => resp.json()) .then(json => console.log(json)) .catch(err => console.log(err));

Here is a full Activity class that places a Marker at the current location, and also moves the camera to the current position. There are a few thing going on in sequence here: Check Location permission Once Location permission is granted, call setMyLocationEnabled(), build the GoogleApiClient, ...

Inspecting system resource usage is an efficient way to find misbehaving applications. This example is an equivalent of the traditional top command for containers: docker stats To follow the stats of specific containers, list them on the command line: docker stats 7786807d8084 7786807d8085 D...

Inspecting system resource usage is an efficient way to narrow down a problem on a live running application. This example is an equivalent of the traditional ps command for containers. docker top 7786807d8084 To filter of format the output, add ps options on the command line: docker top 7786807...

'Attaching to a container' is the act of starting a terminal session within the context that the container (and any programs therein) is running. This is primarily used for debugging purposes, but may also be needed if specific data needs to be passed to programs running within the container. The a...

public class Foo { private IBar _iBar; public IBar iBar { set { _iBar = value; } } public void DoStuff() { _iBar.DoSomething(); } } public interface IBar { void DoSomething(); }

public class Foo { private readonly IBar _iBar; public Foo(IBar iBar) { _iBar = iBar; } public void DoStuff() { _bar.DoSomething(); } } public interface IBar { void DoSomething(); }

Sometimes you want to do something with the exception you catch (like write to log or print a warning) and let it bubble up to the upper scope to be handled. To do so, you can rethrow any exception you catch: try { ... // some code here } catch (const SomeException& e) { std::cout &l...

import pandas as pd import numpy as np np.random.seed(123) x = np.random.standard_normal(4) y = range(4) df = pd.DataFrame({'X':x, 'Y':y}) >>> df X Y 0 -1.085631 0 1 0.997345 1 2 0.282978 2 3 -1.506295 3

A select case construct conditionally executes one block of constructs or statements depending on the value of a scalar expression in a select case statement. This control construct can be considered as a replacement for computed goto. [name:] SELECT CASE (expr) [CASE (case-value [, case-value] .....

To download the entire repository including the full history and all branches, type: git clone <url> The example above will place it in a directory with the same name as the repository name. To download the repository and save it in a specific directory, type: git clone <url> [dire...

Component code: angular.module('myModule', []).component('myComponent', { bindings: { myValue: '<' }, controller: function(MyService) { this.service = MyService; this.componentMethod = function() { return 2; }; } }); The test: describe('myComponent', f...

By default, all types in TypeScript allow null: function getId(x: Element) { return x.id; } getId(null); // TypeScript does not complain, but this is a runtime error. TypeScript 2.0 adds support for strict null checks. If you set --strictNullChecks when running tsc (or set this flag in you...

val num = 42d Print two decimal places for num using f println(f"$num%2.2f") 42.00 Print num using scientific notation using e println(f"$num%e") 4.200000e+01 Print num in hexadecimal with a println(f"$num%a") 0x1.5p5 Other format strings can be found ...

if ([object respondsToSelector:@selector(someOptionalMethodInProtocol:)]) { [object someOptionalMethodInProtocol:argument]; }

Oracle's CONNECT BY functionality provides many useful and nontrivial features that are not built-in when using SQL standard recursive CTEs. This example replicates these features (with a few additions for sake of completeness), using SQL Server syntax. It is most useful for Oracle developers findin...

An implicit conversion allows the compiler to automatically convert an object of one type to another type. This allows the code to treat an object as an object of another type. case class Foo(i: Int) // without the implicit Foo(40) + 2 // compilation-error (type mismatch) // defines how t...