Column#

class pylibcudf.column.Column(DataType data_type, size_type size, gpumemoryview data, gpumemoryview mask, size_type null_count, size_type offset, list children)#

A container of nullable device data as a column of elements.

This class is an implementation of Arrow columnar data specification for data stored on GPUs. It relies on Python memoryview-like semantics to maintain shared ownership of the data it is constructed with, so any input data may also be co-owned by other data structures. The Column is designed to be operated on using algorithms backed by libcudf.

Parameters:

data_typeDataType: The type of data in the column.
sizesize_type: The number of rows in the column.
datagpumemoryview: The data the column will refer to.
maskgpumemoryview: The null mask for the column.
null_countint: The number of null rows in the column.
offsetint: The offset into the data buffer where the column’s data begins.
childrenlist: The children of this column if it is a compound column type.

Methods

`all_null_like`(Column like, size_type size)	Create an all null column from a template.
`child`(self, size_type index)	Get a child column of this column.
`children`(self)	The children of the column.
`copy`(self)	Create a copy of the column.
`data`(self)	The data buffer of the column.
`from_cuda_array_interface_obj`(obj)	Create a Column from an object with a CUDA array interface.
`from_scalar`(Scalar slr, size_type size)	Create a Column from a Scalar.
`list_view`(self)	Accessor for methods of a Column that are specific to lists.
`null_count`(self)	The number of null elements in the column.
`null_mask`(self)	The null mask of the column.
`num_children`(self)	The number of children of this column.
`offset`(self)	The offset of the column.
`size`(self)	The number of elements in the column.
`type`(self)	The type of data in the column.
`with_mask`(self, gpumemoryview mask, ...)	Augment this column with a new null mask.

static all_null_like(Column like, size_type size)#

Create an all null column from a template.

Parameters:

likeColumn: Column whose type we should mimic
sizeint: Number of rows in the resulting column.

Returns:

Column: An all-null column of size rows and type matching like.

child(self, size_type index) → Column#

Get a child column of this column.

Parameters:

indexsize_type: The index of the child column to get.

Returns:

Column: The child column.

children(self) → list#: The children of the column.

copy(self) → Column#: Create a copy of the column.

data(self) → gpumemoryview#: The data buffer of the column.

static from_cuda_array_interface_obj(obj)#

Create a Column from an object with a CUDA array interface.

Parameters:

objobject: The object with the CUDA array interface to create a column from.

Returns:

Column: A Column containing the data from the CUDA array interface.

Notes

Data is not copied when creating the column. The caller is responsible for ensuring the data is not mutated unexpectedly while the column is in use.

static from_scalar(Scalar slr, size_type size)#

Create a Column from a Scalar.

Parameters:

slrScalar: The scalar to create a column from.
sizesize_type: The number of elements in the column.

Returns:

Column: A Column containing the scalar repeated size times.

list_view(self) → ListColumnView#: Accessor for methods of a Column that are specific to lists.

null_count(self) → size_type#: The number of null elements in the column.

null_mask(self) → gpumemoryview#: The null mask of the column.

num_children(self) → size_type#: The number of children of this column.

offset(self) → size_type#: The offset of the column.

size(self) → size_type#: The number of elements in the column.

type(self) → DataType#: The type of data in the column.

with_mask(self, gpumemoryview mask, size_type null_count) → Column#

Augment this column with a new null mask.

Parameters:

maskgpumemoryview: New mask (or None to unset the mask)
null_countint: New null count. If this is incorrect, bad things happen.

Returns:

New Column object sharing data with self (except for the mask which is new).

class pylibcudf.column.ListColumnView(Column col)#

Accessor for methods of a Column that are specific to lists.

Methods

`child`(self)	The data column of the underlying list column.
`offsets`(self)	The offsets column of the underlying list column.

child(self)#: The data column of the underlying list column.

offsets(self)#: The offsets column of the underlying list column.

pylibcudf.column.is_c_contiguous(shape: Sequence[int], strides: Sequence[int], int itemsize: int) → bool#

Determine if shape and strides are C-contiguous

Parameters:

shapeSequence[int]: Number of elements in each dimension.
stridesSequence[int]: The stride of each dimension in bytes.
itemsizeint: Size of an element in bytes.

Returns:

bool: The boolean answer.