datatable.sort()¶
Sort clause for use in Frame’s square-bracket selector.
When a sort()
object is present inside a DT[i, j, ...]
expression, it will sort the rows of the resulting Frame according
to the columns cols
passed as the arguments to sort()
.
When used together with by()
, the sort clause applies after the
group-by, i.e. we sort elements within each group. Note, however,
that because we use stable sorting, the operations of grouping and
sorting are commutative: the result of applying groupby and then sort
is the same as the result of sorting first and then doing groupby.
When used together with i
(row filter), the i
filter is
applied after the sorting. For example,:
DT[:10, :, sort(f.Highscore, reverse=True)]
will select the first 10 records from the frame DT
ordered by
the Highscore column.