Tutorial by Examples: co

Coalesce basic Example

COALESCE() returns the first NON NULL value in a list of arguments. Suppose we had a table containing phone numbers, and cell phone numbers and wanted to return only one for each user. In order to only obtain one, we can get the first NON NULL value. DECLARE @Table TABLE (UserID int, PhoneNumber va...

Test if cookies are enabled

If you want to make sure cookies are enabled before using them, you can use navigator.cookieEnabled: if (navigator.cookieEnabled === false) { alert("Error: cookies not enabled!"); } Note that on older browsers navigator.cookieEnabled may not exist and be undefined. In those case...

Installation with composer

TYPO3 can be solely installed with the PHP dependency manager composer. Composer has to be available on the server, then a TYPO3 project can be started by using the base distribution. composer create-project typo3/cms-base-distribution . This will pull the TYPO3 core from the git repository, dow...

List of Comparison Operators

OperatorComparisonExample==Equali == 0===Equal Value and Typei === "5"!=Not Equali != 5!==Not Equal Value or Typei !== 5>Greater thani > 5<Less thani < 5>=Greater than or equali >= 5<=Less than or equali <= 5

Overview of the basic path drawing commands: lines and curves

================== TODO: Link each of the drawing commands below to their individual examples. I don't know how to do this since the links to the individual examples point towards the "draft" folder. TODO: Add examples for these path "action" commands: stroke(), fill(), clip() ...

lineTo (a path command)

context.lineTo(endX, endY) Draws a line segment from the current pen location to coordinate [endX,endY] <!doctype html> <html> <head> <style> body{ background-color:white; } #canvas{border:1px solid red; } </style> <script> window.onload=(fun...

arc (a path command)

context.arc(centerX, centerY, radius, startingRadianAngle, endingRadianAngle) Draws a circular arc given a centerpoint, radius and starting & ending angles. The angles are expressed as radians. To convert degrees to radians you can use this formula: radians = degrees * Math.PI / 180;. Angle ...

quadraticCurveTo (a path command)

context.quadraticCurveTo(controlX, controlY, endingX, endingY) Draws a quadratic curve starting at the current pen location to a given ending coordinate. Another given control coordinate determines the shape (curviness) of the curve. <!doctype html> <html> <head> <style...

bezierCurveTo (a path command)

context.bezierCurveTo(control1X, control1Y, control2X, control2Y, endingX, endingY) Draws a cubic Bezier curve starting at the current pen location to a given ending coordinate. Another 2 given control coordinates determine the shape (curviness) of the curve. <!doctype html> <html&gt...

arcTo (a path command)

context.arcTo(pointX1, pointY1, pointX2, pointY2, radius); Draws a circular arc with a given radius. The arc is drawn clockwise inside the wedge formed by the current pen location and given two points: Point1 & Point2. A line connecting the current pen location and the start of the arc is au...

rect (a path command)

context.rect(leftX, topY, width, height) Draws a rectangle given a top-left corner and a width & height. <!doctype html> <html> <head> <style> body{ background-color:white; } #canvas{border:1px solid red; } </style> <script> window.onload...

closePath (a path command)

context.closePath() Draws a line from the current pen location back to the beginning path coordinate. For example, if you draw 2 lines forming 2 legs of a triangle, closePath will "close" the triangle by drawing the third leg of the triangle from the 2nd leg's endpoint back to the firs...

beginPath (a path command)

context.beginPath() Begins assembling a new set of path commands and also discards any previously assembled path. It also moves the drawing "pen" to the top-left origin of the canvas (==coordinate[0,0]). Although optional, you should ALWAYS start a path with beginPath The discarding ...

Consuming a Successful Future

The easiest way to consume a successful Future-- or rather, get the value inside the Future-- is to use the map method. Suppose some code calls the divide method of the FutureDivider object from the "Creating a Future" example. What would the code need to look like to get the quotient of...

Consuming a Failed Future

Sometimes the computation in a Future can create an exception, which will cause the Future to fail. In the "Creating a Future" example, what if the calling code passed 55 and 0 to the divide method? It'd throw an ArithmeticException after trying to divide by zero, of course. How would t...

Convert Exceptions into Either or Option Types

To convert exceptions into Either or Option types, you can use methods that provided in scala.util.control.Exception import scala.util.control.Exception._ val plain = "71a" val optionInt: Option[Int] = catching(classOf[java.lang.NumberFormatException]) opt { plain.toInt } val eitherI...

Loading default configuration

To read default configuration properties: package com.example; public class ExampleApplication { private Properties getDefaults() throws IOException { Properties defaults = new Properties(); try (InputStream defaultsStream = ExampleApplication.class.getResou...

Create a View Component

View components encapsulate reusable pieces of logic and views. They are defined by: A ViewComponent class containing the logic for fetching and preparing the data for the view and deciding which view to render. One or more views Since they contain logic, they are more flexible than partial v...

Login View Component

The default project template creates a partial view _LoginPartial.cshtml which contains a bit of logic for finding out whether the user is logged in or not and find out its user name. Since a view component might be a better fit (as there is logic involved and even 2 services injected) the followin...

Showing code snippets and output

Two popular options are to use: ipython notation: In [11]: df = pd.DataFrame([[1, 2], [3, 4]]) In [12]: df Out[12]: 0 1 0 1 2 1 3 4 Alternatively (this is popular over in the python documentation) and more concisely: df.columns # Out: RangeIndex(start=0, stop=2, step=1) df[0...

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