coalescing operator

Nil coalescing operator ?? Is the optional and ternary operators? . For example, an optional string type variable var a:String?// println(a != nil ? a! : "shabi")println(a ?? "shabi") // shabi// a ?? "shabi" equals a != nil ? a! : "shabi"a =

?? "Null coalescing" operator Is a new operator provided by c #. The function provided by this operator is to determine whether the left-side operand is null. If yes, the return result is the right-side operand, and if not null, the left-side

(1), C # syntax of a question mark (?) operator refers to a nullable type. The explanation above MSDN: null to numeric and Boolean types was especially useful when you were dealing with databases an d Other data types, that contain elements, is not

(1), C # each question mark (?) in the syntax (?) Operator refers:It can be a null type.  The above description on msdn: null to numeric and Boolean types is especially useful when you are dealing with databases and other data types that contain

From:http://www.cnblogs.com/zfanlong1314/archive/2012/02/26/2390456.html(1), C # syntax of a question mark (?) Operator refers to a nullable type. The explanation above MSDN: null to numeric and Boolean types was especially useful when you were

Null-value merge operators and interval operators The main things to see today are the basic operators in Swift. Record it. Nil coalescing Operator A?? b in the?? is a null-value merge operator that will judge a and, if not nil, unpack, or return

//Playground-noun:a Place where people can playImport UIKit//Import Foundationvar str="Hello, playground."//Swift new operator Nil coalescing Operator (nil aggregate operator) two-tuple operator it is designed for selectable data, usually in the

The "null coalescing" operator is a new operator provided by C # that provides the ability to determine whether the operand on the left is null, and if so, the result is the operand on the right, and Non-null returns the operand on the left. We can

Field initializers You can assign values directly to values or objects. We recommend that you do not assign values to the filed initialzer directly. When Inheritance occurs, the order will be weird: Solution: assign values to filed in

//Playground-noun:a Place where people can playImport UIKit//Basic Operators//There are 3 types of operators: Monocular operators (such as-a), two-mesh operators (such as A+b), and three-mesh operators (a? b:c)Let (x, y)= ( -, -)//decomposing