The boundary points are start & end and both of them are included in the range. In the mathematical sense, a range is a sequence of numbers, characters, etc. This can be used to guarantee that an expression won't return a null value, as you'll provide a non-nullable value if the provided value is null.In this tutorial, we will discuss about range in Kotlin.

If it is null, then the second operand will be returned. If first operand isn't null, then it will be returned. It enables you to write a consise code, and works as such: The Elvis Operator is represented by a question mark followed by a colon: ?: and it can be used with this syntax: first operand ?: second operand X ?: throw SomeException() // yields `x` if `x` is not null, throws SomeException otherwise If the second operand is null, the operator is also able to throw an exception.Īn example: x ?: y // yields `x` if `x` is not null, `y` otherwise. Otherwise the value of the second operand (which may be null) is returned.

If the resulting object reference is not null, it is returned. Instead of the first operand having to result in a boolean, it must result in an object reference. Some computer programming languages have different semantics for this operator. The following is especially true for Kotlin: It is a variant of the ternary conditional operator, ? :, found in those languages (and many others): the Elvis operator is the ternary operator with its second operand omitted. In certain computer programming languages, the Elvis operator ?: is a binary operator that returns its first operand if that operand is true, and otherwise evaluates and returns its second operand. I find the Wikipedia definition pretty accurate: The Elvis operator is part of many programming languages, e.g. Additionally, the operator can throw an exception if null is returned. TL DR: If the resulting object reference is not null, it is returned.

Kotlin range operator