![]() You can use it in combination with the Elvis operator. Note that if the variable is a mutable property, you won't be able to smart cast it to its non-nullable type inside the if statement (because the value might have been modified by another thread) and you'd have to use the safe call operator with let instead. Therefore when comparing to null, the structural equality a = null is translated to a referential equality a = null.Īccording to the docs, there is no point in optimizing your code, so you can use a = null and a != null The method below demonstrates how to use the firstOrNull() method.A structural equality a = b is translated to a?.equals(b) ?: (b = null) If no element matches the given predicate function, then null is returned. This method returns the first element from the list that satisfies the provided the predicate. Otherwise returns the result of calling block. Instead, we have boxed primitive types like Int and Boolean. This method takes a predicate function as an argument. Kotlin ifNull and ifNullAlso functions Raw ifnull.kt / If this is not null, returns this. In Kotlin, there are no primitive data types such as int or boolean in Java. Syntax to get the first element that matches the predicate fun List.firstOrNull( We and our partners use data for Personalised ads and content, ad and content measurement, audience insights and product development. Start Your Free Software Development Course. We and our partners use cookies to Store and/or access information on a device. Returns the first element if the ArrayList is not empty. The null is the type of reference so it accepts only the nullable values. ![]() ![]() Syntax to get the first element // to get first element If no element matches the provided predicate function, then null is returned. To get the first element of the ArrayList that satisfies the provided predicate function Predicate is a Functional interface, which takes one argument and returns either true or false based on the condition defined.If the ArrayList is empty, then null is returned. Checking for null in conditions First, you can explicitly check whether b is null, and handle the two options separately: val l if (b null) b. To get the first element of the ArrayList.The firstOrNull() method can be used in two ways. ![]()
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