iOS-Swift Blog

Apple says "Optional chaining is a process for querying and calling properties, methods, and subscripts on an optional that might currently be nil" . While processing if optional has value then the process will succeed otherwise the process will return nil . This querying, calling properties, methods and subscribe can be chained together and it failed gracefully if chain returns nil . An Alternative to Forced unwrapping: you will add question mark '?' after the optional value on which property you will wish to call properties, method, and subscripts if the optional is non- nil . Could an important interview question - The main difference between optional chaining and forced unwrapping is optional chaining fails gracefully whereas forced unwrapping will give runtime error when the optional value is nil . The result of optional chaining will return the same type value but that value will be wrapped with optional. So if Int is return t...

Some people found it very confusing initially but when you will understand then it is simple. As we know optional tells itself about it. It's two cases. The first case when a value can be present for a type, then we need to unwrap if need to use it. Second case when a value can not be present for a type. We use '?' to mark a value as optional. class Student {     var name: String ? //  name becomes optional } When you declare the name string as optional by marking ' ? ' then it's valued automatically is set to nil.  NOTE: Swift 'nil' is not same as objective c 'nil'. In Objective-C, it is a pointer to an object which does not exist whereas in swift it's just an absence of a value for a type. let person = Student() print( person .name) When you access the name it will print a  nil . As there is no value assigned to name. Once we will provide a value to name, let say, "Swift". Then it looks like....