How do I filter by an enum class in kotlin? (just learning)
In the code below the enum class defined earlier in the file is PayStatus{PAID,UNPAID}.
fun nextRentDate(): LocalDate? {
return rentPaymentSchedule.
filter { it.value.paymentStatus is PayStatus.UNPAID}.
minBy { it.value.date.toEpochDay() }?.value?.date
}
I get the error: Kotlin:
Incompatible types: PayStatus.UNPAID and Enum
You must use the == operator when checking for enum values !
=== though it's essentially the same thing when it comes to enumsThe is keyword should be used for type comparison, as described here.
Using the operator for comparisons isn't possible as the compiler complains:
'is' over enum entry is not allowed, use comparison instead
Comparison in Kotlin comes in two flavors: == and ===
The first option, == is compiled down to equals(), whereas the latter, ===, is equivalent to Java's == (comparing references).
As we know, this doesn't really make a difference with enums, as you can read in this answer.
==(or even===here), notis. is is for type checking (instanceof in Java). kotlinlang.org/docs/reference/typecasts.html, kotlinlang.org/docs/reference/equality.html==but was getting a different error, the root problem was that I had defined enum class in both the state file, and the contract file, so it was getting overridden by the wrong file defined enum class. all sorted, thanks!!