How to check if a sequence is empty in Kotlin

Question

How to check if a sequence is empty in Kotlin? What's the simplest way?

Alexey Romanov · Accepted Answer · 2019-10-24 18:28:55Z

18

If you mean literally a Sequence, use none() without arguments for "is empty" and any() for "is not empty".

For other collections, these method names work as well, but there's also isNotEmpty(). Strangely, there is isEmpty, but only for arrays!

answered Oct 24, 2019 at 17:59

Alexey Romanov

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Comments

Shreck Ye · Accepted Answer · 2019-10-24 15:40:50Z

2

!sequence.iterator().hasNext()

answered Oct 24, 2019 at 15:40

Shreck Ye

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I am not sure whether this is the simplest way. I don't know why there isn't an isEmpty extension function for sequences.

Careful with this method. If the sequence is an "only once" sequence, then any successive call to iterator() will fail.