<Can’t find a good answer in SO> What’s an idiomatic way to check if a list (or set) contains ...

# getting-started

[allan.conda]

<Can’t find a good answer in SO>
What’s an idiomatic way to check if a list (or set) contains only one specific value?
anything better than checkedSet.contains(value) && checkedSet.size == 1?

[Radoslaw Juszczyk]

what about .filter{it==value}.size == 1 ?

[thanksforallthefish]

checkedSet == setOf(value) ?

[allan.conda]

I see… So far I got checkSet.singleOrNull { it == value } != null but I’m not liking the null check lol

[Radoslaw Juszczyk]

aa so in case of listOf("A","B").containsOnlyOneSpecificValue("A") you expect false?

[allan.conda]

yes

[Radoslaw Juszczyk]

then: checkedSet.singleOrNull()==value

[allan.conda]

Oh…. yeah…

[Radoslaw Juszczyk]

null==value will give you false so you are safe

[allan.conda]

yeah, the value is an enum, can’t be null

[allan.conda]

Thanks a lot!