Tutorial by Examples: u

The angular.isElement returns true if the argument passed to it is a DOM Element or a jQuery wrapped Element. angular.isElement(elem) This function is useful to type check if a passed argument is an element before being processed as such. Examples: angular.isElement(document.querySelector(&q...

iText for Java Importing the iText jars from the Central Maven Repository is the best way to install iText 7. These simple videos explain how to do this using different IDEs: How to import iText 7 in Eclipse to create a Hello World PDF? How to import iText 7 in Netbeans to create a Hello World ...

Behaviours are a list of functions specifications that another module can implement. They are similar to interfaces in other languages. Here’s an example behaviour: defmodule Parser do @callback parse(String.t) :: any @callback extensions() :: [String.t] end And a module that implements ...

POSIX/IEEE Open Group Base Specification says: [2addr] s/BRE/replacement/flags Substitute the replacement string for instances of the BRE in the pattern space. Any character other than backslash or newline can be used instead of a slash to delimit the BRE and the replacement. Within the BRE a...

Create a group of checkboxes that can be used to toggle multiple choices independently. The server will receive the input as a character vector of the selected values. library(shiny) ui <- fluidPage( checkboxGroupInput("checkGroup1", label = h3("This is a Checkbox group&...

Types can represents various kind of things. It can be a single data, a set of data or a function. In F#, we can group the types into two categories.: F# types: // Functions let a = fun c -> c // Tuples let b = (0, "Foo") // Unit type let c = ignore // Records...

1. Add Devise Gem Open up your Gemfile and add this line gem 'devise' Then run; bundle install 2. Set up devise in your app Run the following command in the terminal rails g devise:install 3. Configure Devise Ensure you have defined default url options in your environments files. Open...

In order to ssh into a server your identity's public key has to be added to the list of trusted keys. Most commonly this is done per-user: ssh-copy-id -i ~/.ssh/<identity>.pub <user>@<hostname> Which can be also done manually: cat ~/.ssh/<identity>.pub | ssh <user>...

Coming from imperative languages many developers wonder how to write a for-loop that exits early as F# doesn't support break, continue or return. The answer in F# is to use tail-recursion which is a flexible and idiomatic way to iterate while still providing excellent performance. Say we want to ...

The following function is returning another function as its result which can be later assigned to a variable and called: func jediTrainer () -> ((String, Int) -> String) { func train(name: String, times: Int) -> (String) { return "\(name) has been trained in the Force \(times)...

Every function has its own function type, made up of the parameter types and the return type of the function itself. For example the following function: func sum(x: Int, y: Int) -> (result: Int) { return x + y } has a function type of: (Int, Int) -> (Int) Function types can thus be use...

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...

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...

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...

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...

Like in many other languages, Python uses the % operator for calculating modulus. 3 % 4 # 3 10 % 2 # 0 6 % 4 # 2 Or by using the operator module: import operator operator.mod(3 , 4) # 3 operator.mod(10 , 2) # 0 operator.mod(6 , 4) # 2 You can also use negative nu...