Programming interface

The instance stores a pointer to table implementation that holds all property values and data
The reference count indicating how many table objects refer to the same implementation.
The table increments the reference count for it to be equal to the number of table objects sharing the same implementation.
The table decrements the reference count when the table goes out of the scope. If the reference count is zero, the table frees its implementation.

class

table

Constructors

table

()

An empty table constructor: creates the table instance with zero number of rows and columns.

table

(

const

table&) = default

Creates a new table instance that shares the implementation with another one.

table

(table&&)

Creates a new table instance and moves implementation from another one into it.

Public Methods

table &

operator=

(

const

table&) = default

Replaces the implementation by another one.

table &

operator=

(table&&)

Swaps the implementation of this object and another one.

bool

has_data

()

const

noexcept

Indicates whether a table contains non-zero number of rows and columns.

std::int64_t

get_column_count

()

const

The number of columns in the table.

std::int64_t

get_row_count

()

const

The number of rows in the table.

const

table_metadata &

get_metadata

()

const

The metadata object that holds additional information about the data within the table.

std::int64_t

get_kind

()

const

The runtime id of the table type. Each table sub-type has its unique

kind

. An empty table has a unique

kind

value as well.

data_layout

get_data_layout

()

const

The layout of the data within the table.

class

table_metadata

Constructors

table_metadata

()

Creates the metadata instance without information about the features. The

feature_count

should be set to zero. The

data_type

and

feature_type

properties should not be initialized.

table_metadata

(

const

dal::array<data_type> &

dtypes

,

const

dal::array<feature_type> &

ftypes

)

Creates the metadata instance from external information about the data types and the feature types.

Parameters

dtypes
– The data types of the features. Assigned into the
data_type
property.
ftypes
– The feature types. Assigned into the
feature_type
property.

Preconditions

dtypes.get_count() == ftypes.get_count()

Public Methods

std::int64_t

get_feature_count

()

const

The number of features that metadata contains information about.

const

feature_type &

get_feature_type

(std::int64_t

feature_index

)

const

Feature types in the metadata object. Should be within the range

[0, feature_count)

.

const

data_type &

get_data_type

(std::int64_t

feature_index

)

const

Data types of the features in the metadata object. Should be within the range

[0, feature_count)

.

enum class data_layout { unknown, row_major, column_major };

data_layout::unknown

Represents the data layout that is undefined or unknown at this moment.

data_layout::row_major

The data block elements are stored in raw-major layout.

data_layout::column_major

The data block elements are stored in column_major layout.

enum class feature_type { nominal, ordinal, interval, ratio };

feature_type::nominal

Represents the type of Nominal feature.

feature_type::ordinal

Represents the type of Ordinal feature.

feature_type::interval

Represents the type of Interval feature.

feature_type::ratio

Represents the type of Ratio feature.

Homogeneous table
Programming interface