In that case mappingnullwill fail with a NPE. Emitting null is convenient when returning.
It’s very similar to the very first solution I proposed, but here you wouldn’t allocate an intermediary data structure. The problem could be if the map is not backed by a java map but by a custom implementation in kotlin. There is another method for getting not null value from map: funMapping from one object to another where one or more of the fields may be null. This removes the cast, but at the cost of an additional intermediary data structure: val map3: Map = map2.filterValues. Kotlin also provides various extension functions to work with maps: Accessing Values You can access values in a map using the key, like so: val map mapOf ('one' to 1, 'two' to 2, 'three'. Querying something from a database by primary key which may return no record. NoSuchElementException when the map doesn't contain a value for the specified key and no implicit default value was provided for that map.First, I think this cast is perfectly fine there. Googles developer keynote at its IO show on Wednesday focused on Android and on web technology, which suddenly looks much more capable thanks to WebGPU, an API that allows web applications to tap into local GPU hardware. If you want to provide a default value for missing keys, you can use the getOrDefault () function instead: val myValue3 myMap.getOrDefault('pear', 0) In this example, we use the getOrDefault () function to retrieve the value associated with the key 'pear'. Kotlin consumers where the return types of APIs are no longer nullable. map() is a method in Java Optionals class that applies the function inside the parentheses to the object that is calling it. If the key is not found in the map, both methods will return null. GetValue() function returns the value for the given key or throws an exception if there is no such key in the map. The migration can be performed per configuration and does not have to be done in.
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