Column

class cudf._lib.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 cudf._lib.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.

cudf._lib.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.