Tutorial by Examples: el

#!/bin/bash NO_SNAPSHOTS="No snapshots have been taken yet" SNAPSHOT_OUTPUT=$(vagrant snapshot list | grep "${NO_SNAPSHOTS}") if [ -z "${SNAPSHOT_OUTPUT}" ]; then echo "Found some snapshots, going to remove them" for SNAPSHOT in $(vagrant snap...

Add the following line to ViewDidLoad method: print(Realm.Configuration.defaultConfiguration.fileURL!) The line above will print the location to Xcode's console. Copy the file path, go to Finder → Go → Go to Folder... (or ⌘+⇧+G)→ paste the path and hit Go.

Log the realm file location using: NSLog(@"%@",[RLMRealmConfiguration defaultConfiguration].fileURL); The line above will print the location to Xcode's console. Copy the file path, go to Finder → Go → Go to Folder... (or ⌘+⇧+G)→ paste the path and hit Go.

Problem # models.py: class Library(models.Model): name = models.CharField(max_length=100) books = models.ManyToManyField(Book) class Book(models.Model): title = models.CharField(max_length=100) # views.py def myview(request): # Query the database. libraries = Librar...

Problem Django querysets are evaluated in a lazy fashion. For example: # models.py: class Author(models.Model): name = models.CharField(max_length=100) class Book(models.Model): author = models.ForeignKey(Author, related_name='books') title = models.CharField(max_length=100) ...

There are places in the standard where an object is copied or moved in order to initialize an object. Copy elision (sometimes called return value optimization) is an optimization whereby, under certain specific circumstances, a compiler is permitted to avoid the copy or move even though the standard...

C++17 Normally, elision is an optimization. While virtually every compiler support copy elision in the simplest of cases, having elision still places a particular burden on users. Namely, the type who's copy/move is being elided must still have the copy/move operation that was elided. For example:...

If you return a prvalue expression from a function, and the prvalue expression has the same type as the function's return type, then the copy from the prvalue temporary can be elided: std::string func() { return std::string("foo"); } Pretty much all compilers will elide the tempor...

When you pass an argument to a function, and the argument is a prvalue expression of the function's parameter type, and this type is not a reference, then the prvalue's construction can be elided. void func(std::string str) { ... } func(std::string("foo")); This says to create a tem...

If you return an lvalue expression from a function, and this lvalue: represents an automatic variable local to that function, which will be destroyed after the return the automatic variable is not a function parameter and the type of the variable is the same type as the function's return type ...

If you use a prvalue expression to copy initialize a variable, and that variable has the same type as the prvalue expression, then the copying can be elided. std::string str = std::string("foo"); Copy initialization effectively transforms this into std::string str("foo"); (th...

public class Foo { private const int TASK_ITERATION_DELAY_MS = 1000; private CancellationTokenSource _cts; public Foo() { this._cts = new CancellationTokenSource(); } public void StartExecution() { Task.Factory.StartNew(this.OwnCodeCancelable...

public class Foo { private CancellationTokenSource _cts; public Foo() { this._cts = new CancellationTokenSource(); } public void StartExecution() { Task.Factory.StartNew(this.OwnCodeCancelableTask, this._cts.Token); } public void Cance...

String hubUrl = "http://localhost:4444/wd/hub" DesiredCapabilities capability = DesiredCapabilities.firefox(); //or which browser you want RemoteWebDriver driver = new RemoteWebDriver(hubUrl, capability);

Creating a hub A quick configuration for a hub and node setup in selenium grid. For more information see: Grid 2 docs Requirements To set up a grid hub you need the flowing: Selenium-server-standalone-.jar Creating the hub To Create a Hub you need to run the selenium server. Download Se...

SELECT Name FROM Customers WHERE PhoneNumber IS NULL Selection with nulls take a different syntax. Don't use =, use IS NULL or IS NOT NULL instead.

' The OrElse operator is the homologous of AndAlso. It lets us perform a boolean ' comparison evaluating the second condition only if the first one is False If testFunction(5) = True OrElse otherFunction(4) = True Then ' If testFunction(5) is True, otherFunction(4) is not called. ' In...

A true relational database must go beyond throwing data into a few tables and writing some SQL statements to pull that data out. At best a badly designed table structure will slow the execution of queries and could make it impossible for the database to function as intended. A database table shoul...

Common Lisp REPL is an interactive environment. Every form written after the prompt is evaluated, and its value is afterwards printed as result of the evaluation. So the simplest possible “Hello, World!” program in Common Lisp is: CL-USER> "Hello, World!" "Hello, World!" CL...

class Person(models.Model): name = models.CharField(max_length=50) description = models.TextField() class Club(models.Model): name = models.CharField(max_length=50) members = models.ManyToManyField(Person) Here we define a relationship where a club has many Persons and memb...