Tutorial by Examples: n

Every object in R is assigned a class. You can use class() to find the object's class and str() to see its structure, including the classes it contains. For example: class(iris) [1] "data.frame" str(iris) 'data.frame': 150 obs. of 5 variables: $ Sepal.Length: num 5.1 4.9 4.7 4...

Problem: When you use many labels inside a view, you maybe get a warning: How can we fix this warning? Solution: We calculate and set the priorities in order. The priorities must be different from labels. It means which is important will get higher priority. For example, in my case, I set the ve...

Step 1: In Xcode: File -> New -> File -> Resource -> GPX File -> Next -> Give the GPX file a name(It's Taipei in this example) -> Create Step 2: Edit the GPX file <?xml version="1.0"?> <gpx version="1.1" creator="Xcode"> <wpt ...

Often in R you'll want to know things about an object or variable you're working with. This can be useful when reading someone else's code or even your own, especially when using packages that are new to you. Suppose we create a variable a: a <- matrix(1:9, 3, 3) What data type is this? Yo...

Often data comes in tables. Generally one can divide this tabular data in wide and long formats. In a wide format, each variable has its own column. PersonHeight [cm]Age [yr]Alison17820Bob17445Carl18231 However, sometimes it is more convenient to have a long format, in which all variables are in o...

The Oracle Java Style Guide states: Modifiers should not be written out when they are implicit. (See Modifiers in Oracle Official Code Standard for the context and a link to the actual Oracle document.) This style guidance applies particularly to interfaces. Let's consider the following code ...

In this exercise, we will generate four bootstrap linear regression models and combine the summaries of these models into a single data frame. library(broom) #* Create the bootstrap data sets BootData <- lapply(1:4, function(i) mtcars[sample(1:nrow(mtcars), ...

Ordered sequences may hurt performance when dealing with a large number of elements. To mitigate this, it's possible to call AsUnordered when the sequence order is no longer necessary. var sequence = Enumerable.Range(1, 10000).Select(x => -1 * x); // -1, -2, ... var evenNumbers = sequence.AsPar...

Derives from DispatcherObject Key members public object GetValue(DependencyProperty dp); public void SetValue(DependencyProperty dp, object value); Summary Classes derived from DependencyObject participate in the dependency property system, which includes registering dependency properties ...

a, b = 1, 2 import math math.sin(a) # returns the sine of 'a' in radians # Out: 0.8414709848078965 math.cosh(b) # returns the inverse hyperbolic cosine of 'b' in radians # Out: 3.7621956910836314 math.atan(math.pi) # returns the arc tangent of 'pi' in radians # Out: 1.2626272556789...

A typical use case for SpriteKit is where the SKView fills the whole screen. To do this in Xcode's Interface Builder, first create a normal ViewController, then select the contained view and change its Class from UIView to SKView: Within the code for the View Controller, in the viewDidLoad metho...

One might argue that there are greater resource hogs in Unity than the humble string, but it is one of the easier aspects to fix early on. String operations build garbage Most string operations build tiny amounts of garbage, but if those operations are called several times over the course of a s...

The power of idling resources lies in not having to wait for some app's processing (networking, calculations, animations, etc.) to finish with sleep(), which brings flakiness and/or prolongs the tests run. The official documentation can be found here. Implementation There are three things that you...

fastlane is an open source build automation tool for Android and iOS for developers. It reduce your build generation time. It is a command line tool that uses Ruby, so you need Ruby on your computer. Most Macs already have Ruby installed by default. Install fastlane Open a terminal. Run sudo ge...

2 Dimensional arrays 6 In ES6, we can flatten the array by the spread operator ...: function flattenES6(arr) { return [].concat(...arr); } var arrL1 = [1, 2, [3, 4]]; console.log(flattenES6(arrL1)); // [1, 2, 3, 4] 5 In ES5, we can acheive that by .apply(): function flatten(arr) { ...

As Angular uses HTML to extend a web page and plain Javascript to add logic, it makes it easy to create a web page using ng-app, ng-controller and some built-in directives such as ng-if, ng-repeat, etc. With the new controllerAs syntax, newcomers to Angular users can attach functions and data to the...

This is the basic HTML file that can be used as a boilerplate when starting a project. This boilerplate uses orbit controls with damping (camera that can move around an object with deceleration effect) and creates a spinning cube. <!DOCTYPE html> <html> <head> <t...

public function drawDisplayObjectUsingBounds(source:DisplayObject):BitmapData { var bitmapData:BitmapData;//declare a BitmapData var bounds:Rectangle = source.getBounds(source);//get the source object actual size //round bounds to integer pixel values (to aviod 1px str...

One of the most common errors in compilation happens during the linking stage. The error looks similar to this: $ gcc undefined_reference.c /tmp/ccoXhwF0.o: In function `main': undefined_reference.c:(.text+0x15): undefined reference to `foo' collect2: error: ld returned 1 exit status $ So l...

UIBezierPath using to create a circular path ShapeLayer CAShapeLayer *circleLayer = [CAShapeLayer layer]; [circleLayer setPath:[[UIBezierPath bezierPathWithOvalInRect: CGRectMake(50, 50, 100, 100)] CGPath]]; circleLayer.lineWidth = 2.0; [circleLayer setStrokeColor:[[UIColor redColor] CGColor]];...