Lists Sort#

group Sorting

Functions

std::unique_ptr<column> sort_lists(
lists_column_view const &source_column,
order column_order,
null_order null_precedence,
rmm::cuda_stream_view stream = cudf::get_default_stream(),
rmm::device_async_resource_ref mr = cudf::get_current_device_resource_ref()
)#

Segmented sort of the elements within a list in each row of a list column.

The source_column child may be of any type whose leaf elements are relationally comparable, including arbitrarily nested LIST and STRUCT children.

source_column            : [{4, 2, 3, 1}, {1, 2, NULL, 4}, {-10, 10, 0}]

Ascending,  Null After   : [{1, 2, 3, 4}, {1, 2, 4, NULL}, {-10, 0, 10}]
Ascending,  Null Before  : [{1, 2, 3, 4}, {NULL, 1, 2, 4}, {-10, 0, 10}]
Descending, Null After   : [{4, 3, 2, 1}, {NULL, 4, 2, 1}, {10, 0, -10}]
Descending, Null Before  : [{4, 3, 2, 1}, {4, 2, 1, NULL}, {10, 0, -10}]
Parameters:

  • source_column – View of the list column to sort

  • column_order – The desired sort order

  • null_precedence – The desired order of null compared to other elements in the list

  • stream – CUDA stream used for device memory operations and kernel launches

  • mr – Device memory resource to allocate any returned objects

Returns:

list column with elements in each list sorted.

std::unique_ptr<column> stable_sort_lists(
lists_column_view const &source_column,
order column_order,
null_order null_precedence,
rmm::cuda_stream_view stream = cudf::get_default_stream(),
rmm::device_async_resource_ref mr = cudf::get_current_device_resource_ref()
)#

Segmented sort of the elements within a list in each row of a list column using stable sort.

Segmented sort of the elements within a list in each row of a list column. The source_column child may be of any type whose leaf elements are relationally comparable, including arbitrarily nested LIST and STRUCT children.

source_column            : [{4, 2, 3, 1}, {1, 2, NULL, 4}, {-10, 10, 0}]

Ascending,  Null After   : [{1, 2, 3, 4}, {1, 2, 4, NULL}, {-10, 0, 10}]
Ascending,  Null Before  : [{1, 2, 3, 4}, {NULL, 1, 2, 4}, {-10, 0, 10}]
Descending, Null After   : [{4, 3, 2, 1}, {NULL, 4, 2, 1}, {10, 0, -10}]
Descending, Null Before  : [{4, 3, 2, 1}, {4, 2, 1, NULL}, {10, 0, -10}]
Parameters:

  • source_column – View of the list column to sort

  • column_order – The desired sort order

  • null_precedence – The desired order of null compared to other elements in the list

  • stream – CUDA stream used for device memory operations and kernel launches

  • mr – Device memory resource to allocate any returned objects

Returns:

list column with elements in each list sorted.