Tutorial by Examples: el

To better understand the semantics of conses and lists, a graphical representation of this kind of structures is often used. A cons cell is usually represented with two boxes in contact, that contain either two arrows that point to the car and cdr values, or directly the values. For instance, the re...

OPENJSON function parses collection of JSON objects and returns values from JSON text as set of rows. If the values in input object are nested, additional mapping parameter can be specified in each column in WITH clause: declare @json nvarchar(4000) = N'[ {"data":{"num":&quot...

When performance is a concern, invoking a method via reflection (i.e. via the MethodInfo.Invoke method) is not ideal. However, it is relatively straightforward to obtain a more performant strongly-typed delegate using the Delegate.CreateDelegate function. The performance penalty for using reflecti...

A _ character in a LIKE clause pattern matches a single character. Query SELECT username FROM users WHERE users LIKE 'admin_'; Result +----------+ | username | +----------+ | admin1 | | admin2 | | admin- | | adminA | +----------+

If the file already exists, it will be overwritten! String fileName = "file.zip"; // name of the file String urlToGetFrom = "http://www.mywebsite.com/"; // URL to get it from String pathToSaveTo = "C:\\Users\\user\\"; // where to put it ...

Query SELECT st.name, st.percentage, CASE WHEN st.percentage >= 35 THEN 'Pass' ELSE 'Fail' END AS `Remark` FROM student AS st ; Result +--------------------------------+ | name | percentage | Remark | +--------------------------------+ | Isha | 67 | Pas...

Many bugs in knockout data binds are caused by undefined properties in a viewmodel. Knockout has two handy methods to retrieve the binding context of an HTML element: // Returns the binding context to which an HTMLElement is bound ko.contextFor(element); // Returns the viewmodel to which ...

To build up an expression like _ => _.Field == "VALUE" at runtime. Given a predicate _ => _.Field and a string value "VALUE", create an expression that tests whether or not the predicate is true. The expression is suitable for: IQueryable<T>, IEnumerable<T>...

def lst = [10, 20, 30, 40] lst.find { it > 25 } // 30. Note: it returns a single value

adb shell am start -n com.android.settings/.DevelopmentSettings Will navigate your device/emulator to the Developer Options section.

/** * Created by Nick Cardoso on 03/08/16. * This is not a complete parcelable implementation, it only highlights the easiest * way to read and write your Enum values to your parcel */ public class Foo implements Parcelable { private final MyEnum myEnumVariable; private final M...

To determine the version of Azure PowerShell that you have installed, run the following: Get-Module -ListAvailable -Name Azure -Refresh This command returns the installed version even when you haven't loaded the Azure PowerShell module in your current PowerShell session.

To preload remote images and ensure that the image is only downloaded once: Glide.with(context) .load(yourUrl) .diskCacheStrategy(DiskCacheStrategy.SOURCE) .preload(); Then: Glide.with(context) .load(yourUrl) .diskCacheStrategy(DiskCacheStrategy.SOURCE) // ALL works her...

Some websites don’t like to be scraped. In these cases you may need to simulate a real user working with a browser. Selenium launches and controls a web browser. from selenium import webdriver browser = webdriver.Firefox() # launch firefox browser browser.get('http://stackoverflow.com/questi...

/* PL/SQL is a core Oracle Database technology, allowing you to build clean, secure, optimized APIs to SQL and business logic. */ set serveroutput on BEGIN DBMS_OUTPUT.PUT_LINE ('Hello World!'); END;

MySQL allows to specify from which table the matching rows must be deleted -- remove only the employees DELETE e FROM Employees e JOIN Department d ON e.department_id = d.department_id WHERE d.name = 'Sales' -- remove employees and department DELETE e, d FROM Emp...

Note: Browsers are in the process of adding a built-in context.ellipse drawing command, but this command is not universally adopted (notably not in IE). The methods below work in all browsers. Draw an ellipse given it's desired top-left coordinate: // draws an ellipse based on x,y being top-left...

<?xml version="1.0" encoding="utf-8"?> <s:Application xmlns:fx="http://ns.adobe.com/mxml/2009" xmlns:s="library://ns.adobe.com/flex/spark" xmlns:mx="library://ns.adobe.com/flex/mx"> <s:Label text="Hello World!&...

When attempting to print something for debugging in vimscript, it is tempting to simply do the following. echo "Hello World!" However, in the context of a complex plugin, there are often many other things happening right after you attempt to print your message, so it is important to ad...

public static void delete (String urlString, String contentType) throws IOException { HttpURLConnection connection = null; try { URL url = new URL(urlString); connection = (HttpURLConnection) url.openConnection(); connection.setDoInpu...