Given this...
dataset = Dataset[{
<|"a" -> 1|>,
<|"a" -> 2|>,
<|"a" -> 3|>,
<|"a" -> 4|>,
<|"a" -> 5|>,
<|"a" -> 6|>,
<|"a" -> 7|>,
<|"a" -> 8|>,
<|"a" -> 9|>
}]
And given that this works...
dataset[[1 ;; -1]]
Then shouldn't this work...
dataset[[1 ;; -1 ;; 2]]
For me, the last input returns...
Missing["PartInvalid", 1 ;; -1 ;; 2]
Just by the way, all three of the above statements work if dataset is defined as follows:
dataset = {
<|"a" -> 1|>,
<|"a" -> 2|>,
<|"a" -> 3|>,
<|"a" -> 4|>,
<|"a" -> 5|>,
<|"a" -> 6|>,
<|"a" -> 7|>,
<|"a" -> 8|>,
<|"a" -> 9|>
}