Tutorial by Examples: r

Files can be written bite- and line-wise using the Files class Path p2 = Paths.get("/home/testuser/File.txt"); List<String> lines = Arrays.asList( new String[]{"First line", "Second line", "Third line"}); Files.write(p2, lines); Files.writ...

When making a bind of something, for example a date you may want to show it in a specific format without messing around with it in the code. To do this we can use the StringFormat property. Here are some examples: Text="{Binding Path=ReleaseDate, StringFormat=dddd dd MMMM yyyy}" This...

Elm defines the following special type variables that have a particular meaning to the compiler: comparable: Comprised of Int, Float, Char, String and tuples thereof. This allows the use of the < and > operators. Example: You could define a function to find the smallest and largest eleme...

There is no single command to rename a MySQL database but a simple workaround can be used to achieve this by backing up and restoring: mysqladmin -uroot -p<password> create <new name> mysqldump -uroot -p<password> --routines <old name> | mysql -uroot -pmypassword <new na...

Renaming a table can be done in a single command: RENAME TABLE `<old name>` TO `<new name>`; The following syntax does exactly the same: ALTER TABLE `<old name>` RENAME TO `<new name>`; If renaming a temporary table, the ALTER TABLE version of the syntax must be used....

Renaming a column can be done in a single statement but as well as the new name, the "column definition" (i.e. its data type and other optional properties such as nullability, auto incrementing etc.) must also be specified. ALTER TABLE `<table name>` CHANGE `<old name>` `<n...

MERGE INTO targetTable t USING sourceTable s ON t.PKID = s.PKID WHEN MATCHED AND NOT EXISTS ( SELECT s.ColumnA, s.ColumnB, s.ColumnC INTERSECT SELECT t.ColumnA, t.ColumnB, s.ColumnC ) THEN UPDATE SET t.Colum...

$ printf '%(%F)T\n' 2016-08-17

$ printf -v now '%(%T)T' $ echo "$now" 12:42:47

Lets create a simple transformation to convert a CSV into an XML file. Our Transformation has to do the following: Read the CSV file Build the greetings message Save the greetings in the XML file Create a Transformation: Here's how to start the Transformation: To the left of the works...

Sometimes when working with linear regression we need to check for non-linearity in the data. One way to do this is to fit a polynomial model and check whether it fits the data better than a linear model. There are other reasons, such as theoretical, that indicate to fit a quadratic or higher order ...

This example demonstrates how pointers can be used for C-like access to C# arrays. unsafe { var buffer = new int[1024]; fixed (int* p = &buffer[0]) { for (var i = 0; i < buffer.Length; i++) { *(p + i) = i; } } } The unsafe keyw...

Addition and subtraction in pointers works differently from integers. When a pointer is incremented or decremented, the address it points to is increased or decreased by the size of the referent type. For example, the type int (alias for System.Int32) has a size of 4. If an int can be stored in add...

In C and C++, the asterisk in the declaration of a pointer variable is part of the expression being declared. In C#, the asterisk in the declaration is part of the type. In C, C++ and C#, the following snippet declares an int pointer: int* a; In C and C++, the following snippet declares an int ...

C# inherits from C and C++ the usage of the symbol -> as a means of accessing the members of an instance through a typed pointer. Consider the following struct: struct Vector2 { public int X; public int Y; } This is an example of the usage of -> to access its members: Vector2...

The criteria that a type must satisfy in order to support pointers (see Remarks) cannot be expressed in terms of generic constraints. Therefore, any attempt to declare a pointer to a type provided through a generic type parameter will fail. void P<T>(T obj) where T : struct { T* p...

So, you have completed installation it's time now to Run you program with it. Netbeans has created a shortcut to your desktop, "Double click" that to open the IDE. To Create a new project 1. Click this button OR Goto: files >> New Project then this window will popup Select...

Digital hardware is built from two types of hardware primitives: Combinatorial gates (inverters, and, or, xor, 1-bit full adders, 1-bit multiplexers...) These logic gates perform a simple boolean computation on their inputs and produce an output. Each time one of their inputs changes, they st...

Implementation of IDatabaseInitializer that is used in EntityFramework by default. As the name implies, it creates the database if none exists. However when you change the model, it throws an exception. Usage: public class MyContext : DbContext { public MyContext() { Database.SetIni...

This implementation of IDatabaseInitializer drops and recreates the database if the model changes automatically. Usage: public class MyContext : DbContext { public MyContext() { Database.SetInitializer(new DropCreateDatabaseIfModelChanges<MyContext>()); } }