Tutorial by Examples: e

Any text following a " character on the same line is commented out: DATA ls_booking TYPE flightb. " Commented text

The * character comments out an entire line. The * must be the first character in the line. * DATA ls_booking TYPE flightb. Nothing on this line will be executed.

Detailed instructions on getting domain-driven-design set up or installed.

In certain situations, data declarations can be performed inline. LOOP AT lt_sflight INTO DATA(ls_sflight). WRITE ls_sflight-carrid. ENDLOOP.

DATA begda TYPE sy-datum.

DATA: begda TYPE sy-datum, endda TYPE sy-datum.

A Map is a basic mapping of keys to values. Maps are different from objects in that their keys can be anything (primitive values as well as objects), not just strings and symbols. Iteration over Maps is also always done in the order the items were inserted into the Map, whereas the order is undefine...

Grand Central Dispatch works on the concept of "Dispatch Queues". A dispatch queue executes tasks you designate in the order which they are passed. There are three types of dispatch queues: Serial Dispatch Queues (aka private dispatch queues) execute one task at a time, in order. They a...

3.0 To run tasks on a dispatch queue, use the sync, async, and after methods. To dispatch a task to a queue asynchronously: let queue = DispatchQueue(label: "myQueueName") queue.async { //do something DispatchQueue.main.async { //this will be called in main t...

Display multiple plots in one image with the different facet functions. An advantage of this method is that all axes share the same scale across charts, making it easy to compare them at a glance. We'll use the mpg dataset included in ggplot2. Wrap charts line by line (attempts to create a square l...

ggplot2 works best with a long data frame. The following sample data which represents the prices for sweets on 20 different days, in a format described as wide, because each category has a column. set.seed(47) sweetsWide <- data.frame(date = 1:20, chocolate = run...

Letters 3.0 let letters = CharacterSet.letters let phrase = "Test case" let range = phrase.rangeOfCharacter(from: letters) // range will be nil if no letters is found if let test = range { print("letters found") } else { print("letters not found") }...

A common question is how to juxtapose (combine) physically separate geographical regions on the same map, such as in the case of a choropleth describing all 50 American states (The mainland with Alaska and Hawaii juxtaposed). Creating an attractive 50 state map is simple when leveraging Google Maps...

Java doesn't provide a direct method in java.util.Arrays to remove an element from an array. To perform it, you can either copy the original array to a new one without the element to remove or convert your array to another structure allowing the removal. Using ArrayList You can convert the array t...

The + symbol marks a type parameter as covariant - here we say that "Producer is covariant on A": trait Producer[+A] { def produce: A } A covariant type parameter can be thought of as an "output" type. Marking A as covariant asserts that Producer[X] <: Producer[Y] prov...

By default all type parameters are invariant - given trait A[B], we say that "A is invariant on B". This means that given two parametrizations A[Cat] and A[Animal], we assert no sub/superclass relationship between these two types - it does not hold that A[Cat] <: A[Animal] nor that A[Ca...

The - symbol marks a type parameter as contravariant - here we say that "Handler is contravariant on A": trait Handler[-A] { def handle(a: A): Unit } A contravariant type parameter can be thought of as an "input" type. Marking A as contravariant asserts that Handler[X] &l...

Because collections are typically covariant in their element type*, a collection of a subtype may be passed where a super type is expected: trait Animal { def name: String } case class Dog(name: String) extends Animal object Animal { def printAnimalNames(animals: Seq[Animal]) = { anima...

Java provides specialized Streams for three types of primitives IntStream (for ints), LongStream (for longs) and DoubleStream (for doubles). Besides being optimized implementations for their respective primitives, they also provide several specific terminal methods, typically for mathematical operat...

The static keyword means 2 things: This value does not change from object to object but rather changes on a class as a whole Static properties and methods don't require an instance. public class Foo { public Foo{ Counter++; NonStaticCounter++; } public st...