Tutorial by Examples: en

countMatches method from org.apache.commons.lang3.StringUtils is typically used to count occurences of a substring or character in a String: import org.apache.commons.lang3.StringUtils; String text = "One fish, two fish, red fish, blue fish"; // count occurrences of a substring Str...

Method references allow predefined static or instance methods that adhere to a compatible functional interface to be passed as arguments instead of an anonymous lambda expression. Assume that we have a model: class Person { private final String name; private final String surname; ...

hash( (1, 2) ) # ok hash( ([], {"hello"}) # not ok, since lists and sets are not hashabe Thus a tuple can be put inside a set or as a key in a dict only if each of its elements can. { (1, 2) } # ok { ([], {"hello"}) ) # not ok

The contentSize property must be set to the size of the scrollable content. This specifies the size of the scrollable area. Scrolling is visible when scrollable area i.e. contentSize is larger than the UIScrollView frame size. With Autolayout: When the scroll view's content is set up using autolay...

When referring to a worksheet, a range or individual cells, it is important to fully qualify the reference. For example: ThisWorkbook.Worksheets("Sheet1").Range(Cells(1, 2), Cells(2, 3)).Copy Is not fully qualified: The Cells references do not have a workbook and worksheet associated ...

The Switch statement works very well with Enum values enum CarModel { case Standard, Fast, VeryFast } let car = CarModel.Standard switch car { case .Standard: print("Standard") case .Fast: print("Fast") case .VeryFast: print("VeryFast") } Since we ...

From MSDN: An enumeration type (also named an enumeration or an enum) provides an efficient way to define a set of named integral constants that may be assigned to a variable. Essentially, an enum is a type that only allows a set of finite options, and each option corresponds to a number. By d...

WITH CTE (StudentId, Fname, LName, DOB, RowCnt) as ( SELECT StudentId, FirstName, LastName, DateOfBirth as DOB, SUM(1) OVER (Partition By FirstName, LastName, DateOfBirth) as RowCnt FROM tblStudent ) SELECT * from CTE where RowCnt > 1 ORDER BY DOB, LName This example uses a Common Table ...

CREATE SEQUENCE orders_seq START WITH 1000 INCREMENT BY 1; Creates a sequence with a starting value of 1000 which is incremented by 1.

a reference to seq_name.NEXTVAL is used to get the next value in a sequence. A single statement can only generate a single sequence value. If there are multiple references to NEXTVAL in a statement, they use will use the same generated number. NEXTVAL can be used for INSERTS INSERT INTO Orders (Or...

Once the instance of the BackgroundWorker has been declared, it must be given properties and event handlers for the tasks it performs. /* This is the backgroundworker's "DoWork" event handler. This method is what will contain all the work you wish to have your progra...

Elements come with angle brackets are the most prominent building block of XML. Elements can either be empty, in which case they are made of an empty tag (notice the ending slash): <an-empty-element/> Or they can have content, in which case they have an opening tag (no slash) and a closin...

Extension methods are useful to extend the behaviour of libraries we don't own. They are used similar to instance methods thanks to the compiler's syntactic sugar: Sub Main() Dim stringBuilder = new StringBuilder() 'Extension called directly on the object. stringBuilder.AppendIf(t...

A good use of extension method is to make the language more functional Sub Main() Dim strings = { "One", "Two", "Three" } strings.Join(Environment.NewLine).Print() End Sub <Extension> Public Function Join(strings As IEnumerable(Of String), separa...

In XML, element and attribute names live in namespaces. By default, they are in no namespace: <?xml version="1.0"?> <foo attr="value"> <!-- the foo element is in no namespace, neither is the attr attribute --> </foo>

Single line comments are preceded by --, and go until the end of the line: SELECT * FROM Employees -- this is a comment WHERE FName = 'John'

Multi-line code comments are wrapped in /* ... */: /* This query returns all employees */ SELECT * FROM Employees It is also possible to insert such a comment into the middle of a line: SELECT /* all columns: */ * FROM Employees

As Handlers are used to send Messages and Runnables to a Thread's message queue it's easy to implement event based communication between multiple Threads. Every Thread that has a Looper is able to receive and process messages. A HandlerThread is a Thread that implements such a Looper, for example th...

g$ The above matches one letter (the letter g) at the end of a string in most regex engines (not in Oniguruma, where the $ anchor matches the end of a line by default, and the m (MULTILINE) modifier is used to make a . match any characters including line break characters, as a DOTALL modifier in ...

Elixir doesn't have loops. Instead of them for lists there are great Enum and List modules, but there are also List Comprehensions. List Comprehensions can be useful to: create new lists iex(1)> for value <- [1, 2, 3], do: value + 1 [2, 3, 4] filtering lists, using guard expressi...