Tutorial by Examples: num

The SQL 2008 standard defines the FETCH FIRST clause to limit the number of records returned. SELECT Id, ProductName, UnitPrice, Package FROM Product ORDER BY UnitPrice DESC FETCH FIRST 10 ROWS ONLY This standard is only supported in recent versions of some RDMSs. Vendor-specific non-stand...

By default the Python random module use the Mersenne Twister PRNG to generate random numbers, which, although suitable in domains like simulations, fails to meet security requirements in more demanding environments. In order to create a cryptographically secure pseudorandom number, one can use Syst...

The default value for an enum is zero. If an enum does not define an item with a value of zero, its default value will be zero. public class Program { enum EnumExample { one = 1, two = 2 } public void Main() { var e =...

Imaginary numbers in Python are represented by a "j" or "J" trailing the target number. 1j # Equivalent to the square root of -1. 1j * 1j # = (-1+0j)

In all versions of Python, we can represent infinity and NaN ("not a number") as follows: pos_inf = float('inf') # positive infinity neg_inf = float('-inf') # negative infinity not_a_num = float('nan') # NaN ("not a number") In Python 3.5 and higher, we can also us...

public IEnumerable<int> F1() { for (int i = 0; i < 3; i++) yield return i; //return F2(); // Compile Error!! foreach (var element in F2()) yield return element; } public int[] F2() { return new[] { 3, 4, 5 }; }

Variadic Arguments

One of the very basic animations that you could come across is the NumberAnimation. This animation works by changing the numeric value of a property of an item from an initial state to a final state. Consider the following complete example: import QtQuick 2.7 import QtQuick.Controls 2.0 ...

Not always the enum name is clear enough to be understood. To document an enum, use standard javadoc: /** * United States coins */ public enum Coins { /** * One-cent coin, commonly known as a penny, * is a unit of currency equaling one-hundredth * of a United Sta...

Floating point numbers of type real cannot have any real value. They can represent real numbers up to certain amount of decimal digits. FORTRAN 77 guaranteed two floating point types and more recent standards guarantee at least two real types. Real variables may be declared as real x double prec...

The boolean type cannot be cast to/from any other primitive type. A char can be cast to/from any numeric type by using the code-point mappings specified by Unicode. A char is represented in memory as an unsigned 16-bit integer value (2 bytes), so casting to byte (1 byte) will drop 8 of those bits (...

Numeric primitives can be cast in two ways. Implicit casting happens when the source type has smaller range than the target type. //Implicit casting byte byteVar = 42; short shortVar = byteVar; int intVar = shortVar; long longVar = intvar; float floatVar = longVar; double doubleVar = floatVar...

Each enum class contains an implicit static method named values(). This method returns an array containing all values of that enum. You can use this method to iterate over the values. It is important to note however that this method returns a new array every time it is called. public enum Day { ...

Math.random(); produces an evenly distributed random number between 0 (inclusive) and 1 (exclusive) Example output: 0.22282187035307288 0.3948539895936847 0.9987191134132445

function randomMinMax(min:Number, max:Number):Number { return (min + (Math.random() * Math.abs(max - min))); } This function is called by passing a range of minimum and maximum values. Example: randomMinMax(1, 10); Example outputs: 1.661770915146917 2.5521070677787066 9.4362709657...

Java-like enumerations can be created by extending Enumeration. object WeekDays extends Enumeration { val Mon, Tue, Wed, Thu, Fri, Sat, Sun = Value } def isWeekend(day: WeekDays.Value): Boolean = day match { case WeekDays.Sat | WeekDays.Sun => true case _ => false } isWeekend...

// Integral types as hex string.Format("Hexadecimal: byte2: {0:x2}; byte4: {0:X4}; char: {1:x2}", 123, (int)'A'); // Integers with thousand separators string.Format("Integer, thousand sep.: {0:#,#}; fixed length: >{0,10:#,#}<", 1234567); // Integer with leading zero...

A pseudo-random number generator generates values that can be guessed based on previously generated values. In other words: it is deterministic. Do not use a pseudo-random number generator in situations where a true random number is required. #include <iostream> #include <random> in...

[a-b] where a and b are digits in the range 0 to 9 [3-7] will match a single digit in the range 3 to 7. Matching multiple digits \d\d will match 2 consecutive digits \d+ will match 1 or more consecutive digits \d* will match 0 or more consecutive digits \d{3} will ma...

In its most basic form, an object that implements IEnumerable represents a series of objects. The objects in question can be iterated using the c# foreach keyword. In the example below, the object sequenceOfNumbers implements IEnumerable. It represents a series of integers. The foreach loop iterate...