WhatIf ☔ Fluent expressions of Kotlin for handling single if-else statements, nullable, collections, and boolean. Take Returns a list containing the non-null results of applying the given transform function to each element of the original collection. Kotlin is a modern programming language that compiles to Java bytecode.It is free and open source, and promises to make coding for Android even more fun. Returns true if the element is found in the collection. * @sample samples.collections.Collections.Collections.collectionIsNotEmpty */ @kotlin. In general, one should strive to use read-only lists, however, mutability is still often useful at construction time, especially when dealing with third-party libraries with non-functional interfaces. data?.let { // execute this block if not null } ? internal. : run { // execute this block if null } But this seems not to be quite as readable as a simple if-else statement. 3. I have declared below variables: val occupations = mapOf(Pair("Malcolm", "Captain"), Pair("Kaylee", "Mechanic")) val isNotEmpty (): Boolean = !isEmpty() /* * * Returns `true` if this nullable collection is either null or empty. The top answers here correctly speak to the difference in Kotlin between read-only List (NOTE: it's read-only, not "immutable"), and MutableList. Kotlin™ is protected under the Kotlin Foundation and licensed under the Apache 2 license. dropWhile is another filter that takes a predicate but dropWhile works from index 0 -> n and dropLastWhile works from index n -> 0. Here, you added safe call operators. Gradle. The method stops removing elements as soon as an element does not meet the condition of the predicate. ... As we can see, if we omit the prefix and suffix, they are the empty string, and if we omit the separator, then it is the string “, “. Download ☔ WhatIf has been downloaded in more than 50k Kotlin and Android projects all over the world! Supported and developed by JetBrains Supported and developed by JetBrains If we try to drop more elements than the collection contains, we’ll just be left with an empty List. Add a dependency code to your module's build.gradle file. In this tutorial, we'll continue to learn the language by looking at the ranges and collections API in Kotlin. A quick and practical guide to collection processing in Kotlin. InlineOnly: public inline fun < T > Collection. How can i declare an empty collection for mapOf,listOf and setOf in Kotlin? * Returns `true` if the collection is not empty. [kotlin] assertEquals(listOf(2, 4, 6, 8), listWithNull mapNotNull { it * 2 }) [/kotlin] 18.4 Elements operations contains. We can also specify a limit to the number of elements to combine. 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