Tutorial by Examples: re

Functions can return tuples: func tupleReturner() -> (Int, String) { return (3, "Hello") } let myTuple = tupleReturner() print(myTuple.0) // 3 print(myTuple.1) // "Hello" If you assign parameter names, they can be used from the return value: func tupleReturner(...

In this example we're going to look at testing webhook notifications in sandbox, using ngrok to provide a tunnel for our Node HTTP listener, running on localhost, to the internet. For this example, we're going to be using Node to set up notification webhooks for payment events (such as a payment bei...

Writing bytes to an OutputStream one byte at a time OutputStream stream = object.getOutputStream(); byte b = 0x00; stream.write( b ); Writing a byte array byte[] bytes = new byte[] { 0x00, 0x00 }; stream.write( bytes ); Writing a section of a byte array int offset = 1; int length = ...

Streams provide the most direct access to the binary content, so any InputStream / OutputStream implementations always operate on ints and bytes. // Read a single byte from the stream int b = inputStream.read(); if (b >= 0) { // A negative value represents the end of the stream, normal values ...

Preferences objects always represent a specific node in a whole Preferences tree, kind of like this: /userRoot ├── com │   └── mycompany │   └── myapp │   ├── darkApplicationMode=true │   ├── showExitConfirmation=false │   └── windowMaximized=true └── org └...

All instances of Preferences are always thread-safe across the threads of a single Java Virtual Machine (JVM). Because Preferences can be shared across multiple JVMs, there are special methods that deal with synchronizing changes across virtual machines. If you have an application which is supposed...

Preferences nodes can be exported into a XML document representing that node. The resulting XML tree can be imported again. The resulting XML document will remember whether it was exported from the user or system Preferences. To export a single node, but not its child nodes: Java SE 7 try (Output...

Preferences nodes can be imported from a XML document. Importing is meant to be used in conjunction with the exporting functionality of Preferences, since it creates the correct corresponding XML documents. The XML documents will remember whether they were exported from the user or system Preferenc...

Event listeners can be removed again from any Properties node, but the instance of the listener has to be kept around for that. Java SE 8 Preferences preferences = Preferences.userNodeForPackage(getClass()); PreferenceChangeListener listener = evt -> { System.out.println(evt.getKey() + ...

A value of a Preferences node can be of the type String, boolean, byte[], double, float, int or long. All invocations must provide a default value, in case the specified value is not present in the Preferences node. Preferences preferences = Preferences.userNodeForPackage(getClass()); String som...

To store a value into the Preferences node, one of the putXXX() methods is used. A value of a Preferences node can be of the type String, boolean, byte[], double, float, int or long. Preferences preferences = Preferences.userNodeForPackage(getClass()); preferences.put("someKey", "...

Preferences can be used to store user settings that reflect a user's personal application settings, e.g. their editor font, whether they prefer the application to be started in full-screen mode, whether they checked a "don't show this again" checkbox and things like that. public class Exi...

To add an image to a page, use the image tag. Image tags (img) do not have closing tags. The two main attributes you give to the img tag are src, the image source and alt, which is alternative text describing the image. <img src="images/hello.png" alt="Hello World"> Yo...

foreach is used to iterate over the elements of an array or the items within a collection which implements IEnumerable✝. var lines = new string[] { "Hello world!", "How are you doing today?", "Goodbye" }; foreach (string line in lines) { Con...

When creating animations and other GPU-heavy actions, it's important to understand the will-change attribute. Both CSS keyframes and the transition property use GPU acceleration. Performance is increased by offloading calculations to the device's GPU. This is done by creating paint layers (parts of...

Setting a filter applies to all channels that you will subscribe to from that particular client. This client filter excludes messages that have this subscriber's UUID set at the sender's UUID: NSString *expression = [NSString stringWithFormat:@"(uuid != '%@'", se...

If you want to squash the previous x commits into a single one, you can use the following commands: git reset --soft HEAD~x git commit Replacing x with the number of previous commits you want to be included in the squashed commit. Mind that this will create a new commit, essentially forgetting...

Commits can be squashed during a git rebase. It is recommended that you understand rebasing before attempting to squash commits in this fashion. Determine which commit you would like to rebase from, and note its commit hash. Run git rebase -i [commit hash]. Alternatively, you can type HE...

C++14 Lambdas can capture expressions, rather than just variables. This permits lambdas to store move-only types: auto p = std::make_unique<T>(...); auto lamb = [p = std::move(p)]() //Overrides capture-by-value of `p`. { p->SomeFunc(); }; This moves the outer p variable into th...

If you precede a local variable's name with an &, then the variable will be captured by reference. Conceptually, this means that the lambda's closure type will have a reference variable, initialized as a reference to the corresponding variable from outside of the lambda's scope. Any use of the v...