Dataset¶

Wraps data with type information for structured data handling.

A dataset is queried with the same successive-level operator spec Query takes. An operator that yields a collection gives back a dataset, while one that yields an atom returns it bare.

$ wo 'Normal[Dataset[{<|"a" -> 1|>, <|"a" -> 2|>, <|"a" -> 3|>}][Select[#a > 1 &]]]'
{<|a -> 2|>, <|a -> 3|>}

$ wo 'Dataset[{<|"a" -> 1|>, <|"a" -> 2|>}][Total, "a"]'
3

An integer selects a row:

$ wo 'Normal[Dataset[{<|"a" -> 1|>, <|"a" -> 2|>}][2]]'
<|a -> 2|>