Kotlin Java 8 Stream Equivalents Collect example #5 - find people of legal age, output formatted string
Example
// Java:
String phrase = persons
.stream()
.filter(p -> p.age >= 18)
.map(p -> p.name)
.collect(Collectors.joining(" and ", "In Germany ", " are of legal age."));
System.out.println(phrase);
// In Germany Max and Peter and Pamela are of legal age.
// Kotlin:
val phrase = persons
.filter { it.age >= 18 }
.map { it.name }
.joinToString(" and ", "In Germany ", " are of legal age.")
println(phrase)
// In Germany Max and Peter and Pamela are of legal age.
And as a side note, in Kotlin we can create simple data classes and instantiate the test data as follows:
// Kotlin:
// data class has equals, hashcode, toString, and copy methods automagically
data class Person(val name: String, val age: Int)
val persons = listOf(Person("Tod", 5), Person("Max", 33),
Person("Frank", 13), Person("Peter", 80),
Person("Pamela", 18))
