View to model tabular data. More...

#include <iolink/view/DataFrameView.h>

Inheritance diagram for iolink::DataFrameView:

Public Member Functions
virtual DataFrameCapabilitySet	capabilities () const =0
	Return the view's capabilities.

virtual const Vector2u64 &	shape () const =0
	Return the shape of the data frame.

virtual const std::string &	columnName (size_t index) const =0
	Get the name of a column from its index.

virtual size_t	columnIndex (const std::string &name) const =0
	Get the index of a column from its name.

virtual DataType	columnDataType (size_t index) const =0
	Return the data type of the column.

virtual void	read (size_t column, size_t offset, size_t count, void *dst) const
	Read data from a column.

template<typename T >
T	at (size_t column, size_t row) const
	Get the value stored in a cell of the data frame.

template<typename T >
T	at (const std::string &columnName, size_t row) const
	Get the value stored in a cell of the data frame.

const std::string &	unit (size_t columnIndex)
	Gives the unit of given column.

virtual void	write (size_t column, size_t offset, size_t count, const void *src)
	Write data into a column.

template<typename T >
void	setAt (size_t column, size_t row, T value)
	Set the element value in a cell of the data frame.

template<typename T >
void	setAt (const std::string &columnName, size_t row, T value)
	Set the element value in a cell of the data frame.

void	setUnit (size_t columnIndex, const std::string &unit)
	Set the unit of the column.

virtual void	addColumn (const std::string &name, DataType dtype)
	Add a column to the dataframe.

virtual void	addRows (size_t offset, size_t count)
	Insert rows at the specified position.

virtual void	removeColumn (size_t index)
	Remove a column.

virtual void	removeRows (size_t offset, size_t count)
	Remove a continuous set of rows.

std::string	toString () const
	Return a string representation.

void	reshape (const Vector2u64 &shape, const std::string columnNames, const DataType columnDataTypes)
	Method to reshape a DataFrame.

void	setColumnName (const std::string &columnName, const std::string &newName)
	Set the name of a column identified with its name.

void	setColumnName (size_t index, const std::string &newName)
	Set the name of a column identified with its index.

Public Member Functions inherited from iolink::View
virtual std::shared_ptr< Extension >	extension (size_t id)
	Get an extension of the view, corresponding to the given identifier.

template<typename T >
std::shared_ptr< T >	extension ()
	Get an extension of the view, corresponding to the given type.

std::shared_ptr< ViewOriginExtension >	viewOrigin ()
	Shortcut to access to ViewOrigin extension.

Detailed Description

View to model tabular data.

This view is composed of a set of columns, that have a name and a data type. A column's name is unique, and columns in a dataframe can have different data types.

Each column has the same number of elements. The aggregate of all n-th elements of columns are a row of the dataframe.

Member Function Documentation

◆ addColumn()

virtual void iolink::DataFrameView::addColumn	(	const std::string &	name,
		DataType	dtype
	)

virtual

Add a column to the dataframe.

This method requires the RESHAPE capability.

The new column's data will be undefined after addition.

Parameters

name	The name of the new column.
dtype	The type of data stored in the column.

Exceptions

NotImplemented	When the view does not support reshaping.
Error	if there is already a column with the same name.
Error	if the implementation does not support the data type.

◆ addRows()

virtual void iolink::DataFrameView::addRows	(	size_t	offset,
		size_t	count
	)

virtual

Insert rows at the specified position.

This method requires the RESHAPE capability.

New rows content will be undefined after insertion.

Parameters

offset	New rows will be inserted before this row. If the offset is the number of rows in the dataframe, rows will be inserted at the end.
count	The number of rows to insert.

Exceptions

NotImplemented	When the view does not support reshaping.
Error	When offset is out of bounds.
Error	When it is impossible to add these rows.

◆ at() [1/2]

template<typename T >

T iolink::DataFrameView::at	(	const std::string &	columnName,
		size_t	row
	)		const

inline

Get the value stored in a cell of the data frame.

Template Parameters

T	The type of the data stored in the cell.

Parameters

columnName	The name of the column where to get the cell.
row	The index of the row

Returns: The value of the chosen cell.

Exceptions

Error	if the column name does not exist in the data frame.
Error	if the row is out of bounds.

◆ at() [2/2]

template<typename T >

T iolink::DataFrameView::at	(	size_t	column,
		size_t	row
	)		const

inline

Get the value stored in a cell of the data frame.

Template Parameters

T	The type of the data stored in the cell.

Parameters

column	The index of the column
row	The index of the row

Returns: The value of the cell at the given index.

Exceptions

Error if the column or the cell index is out of bounds.

◆ capabilities()

virtual DataFrameCapabilitySet iolink::DataFrameView::capabilities ( ) const

pure virtual

Return the view's capabilities.

See also: DataFrameCapability

◆ columnDataType()

virtual DataType iolink::DataFrameView::columnDataType ( size_t index ) const

pure virtual

Return the data type of the column.

Parameters

index The index of the column.

Exceptions

Error When index is out of range.

◆ columnIndex()

virtual size_t iolink::DataFrameView::columnIndex ( const std::string & name ) const

pure virtual

Get the index of a column from its name.

Parameters

name	The name of the column.

Exceptions

Error If there is no column with that name.

◆ columnName()

virtual const std::string & iolink::DataFrameView::columnName ( size_t index ) const

pure virtual

Get the name of a column from its index.

Column indices go from 0 to shape[0] - 1.

Parameters

index The index of the column.

Exceptions

Error If index is out of range.

◆ read()

virtual void iolink::DataFrameView::read	(	size_t	column,
		size_t	offset,
		size_t	count,
		void *	dst
	)		const

virtual

Read data from a column.

This method requires the READ capability.

When reading numeric data, the dst buffer will be filled with continuous values. In the case of strings, it will be a continuous array of string objects.

The destination buffer must be allocated by the user. If its size is under the byte count needed to store the request number of elements, a segmentation fault will rise, as there is no boundaries check.

Parameters

column	The index of the column to read from.
offset	The index of the first element to read.
count	The number of elements to read.
dst	A buffer where the read data will be written.

Exceptions

NotImplemented	When the view does not support reading.
Error	When dst is null.
Error	When the column index is invalid.
Error	When offset is out of bounds.
Error	If it is impossible to read the number of elements required.

◆ removeColumn()

virtual void iolink::DataFrameView::removeColumn ( size_t index )

virtual

Remove a column.

This method requires the RESHAPE capability.

Parameters

index The index of the column to remove.

Exceptions

NotImplemented	When the view does not support reshaping.
Error	If the index is out of bounds.
Error	When it is impossible to remove that column.

◆ removeRows()

virtual void iolink::DataFrameView::removeRows	(	size_t	offset,
		size_t	count
	)

virtual

Remove a continuous set of rows.

This method requires the RESHAPE capability.

Parameters

offset	The index of the first column to remove.
count	Row count to delete.

Exceptions

NotImplemented	When the view does not support reshaping.
Error	When offset is out of bounds.
Error	When it is impossible to remove these rows.

◆ reshape()

void iolink::DataFrameView::reshape	(	const Vector2u64 &	shape,
		const std::string *	columnNames,
		const DataType *	columnDataTypes
	)

Method to reshape a DataFrame.

This method requires the RESHAPE capability.

All the dataframe's data is invalidated after this operation.

Parameters

shape	shape of the allocated dataframe (column count, row count)
columnNames	Array which contains the name for each column
columnDataTypes	Array which contains the data type of each column

Warning: No check is done on inputs. Pass arguments very carefully. columnNames and columnDataTypes shall have the same element count, and their size must be equal to shape[0].; column count and row count cannot be 0.

Exceptions

Error if a DataType is not supported.

◆ setAt() [1/2]

template<typename T >

void iolink::DataFrameView::setAt	(	const std::string &	columnName,
		size_t	row,
		T	value
	)

inline

Set the element value in a cell of the data frame.

Template Parameters

T	The type of the data stored in the cell.

Parameters

columnName	The name of the column where to set the cell.
row	The row of the cell to set.
value	The value to store in the cell.

Exceptions

Error	if the column name does not exist in the data frame.
Error	if the row is out of bounds.

◆ setAt() [2/2]

template<typename T >

void iolink::DataFrameView::setAt	(	size_t	column,
		size_t	row,
		T	value
	)

inline

Set the element value in a cell of the data frame.

Template Parameters

T	The type of the data stored in the cell.

Parameters

column	The column of the cell to set.
row	The row of the cell to set.
value	The value to store in the cell.

Exceptions

Error	if the column name does not exist in the data frame.
Error	if the row is out of bounds.

◆ setColumnName() [1/2]

void iolink::DataFrameView::setColumnName	(	const std::string &	columnName,
		const std::string &	newName
	)

Set the name of a column identified with its name.

Parameters

columnName	The name of the column to rename.
newName	The name to assign to the column.

Exceptions

Error	if the given column name does not exist in the DataFrame.
InvalidArgument	if the given new name already exists in the DataFrame.
Error	if DataFrameView does not have the WRITE capability.

◆ setColumnName() [2/2]

void iolink::DataFrameView::setColumnName	(	size_t	index,
		const std::string &	newName
	)

Set the name of a column identified with its index.

Parameters

columnIndex	The index of the column to rename.
newName	The name to assign to the column.

Exceptions

Error	if the given column index is out of range.
InvalidArgument	if the given new name already exists in the DataFrame.
Error	if DataFrameView does not have the WRITE capability.

◆ setUnit()

void iolink::DataFrameView::setUnit	(	size_t	columnIndex,
		const std::string &	unit
	)

Set the unit of the column.

Parameters

columnIndex	The index of the column.
unit	The unit of the column.

Exceptions

Error	if the column index is out of range.
Error	if DataFrameView does not have the WRITE capability.

◆ shape()

virtual const Vector2u64 & iolink::DataFrameView::shape ( ) const

pure virtual

Return the shape of the data frame.

First element being the number of columns, and the second, the number of rows.

◆ unit()

const std::string & iolink::DataFrameView::unit ( size_t columnIndex )

Gives the unit of given column.

Parameters

columnIndex The index of the column.

Returns: The unit of the column if it exists, an empty string otherwise.

Exceptions

Error If the column index is out of bounds.

◆ write()

virtual void iolink::DataFrameView::write	(	size_t	column,
		size_t	offset,
		size_t	count,
		const void *	src
	)

virtual

Write data into a column.

This method requires the WRITE capability.

When writing numeric data, the src buffer must be filled with continuous values. In the case of strings, the source must use a continuous array of string objects.

The source buffer must be allocated by the user. If its size is under the byte count needed to store the request number of elements, a segmentation fault will rise, as there is no boundaries check.

Parameters

column	The index of the column to write into.
offset	The index of the first element to write.
count	The number of element to write.
src	A buffer whose content will be written in the column.

Exceptions

NotImplemented	When the view does not support writing.
Error	When src is null.
Error	When the column index is invalid.
Error	When offset is out of bounds.
Error	If it is impossible to write the number of elements required.

The documentation for this class was generated from the following file:

iolink/public/include/iolink/view/DataFrameView.h

Public Member Functions

Detailed Description

Member Function Documentation

◆ addColumn()

◆ addRows()

◆ at() [1/2]

◆ at() [2/2]

◆ capabilities()

◆ columnDataType()

◆ columnIndex()

◆ columnName()

◆ read()

◆ removeColumn()

◆ removeRows()

◆ reshape()

◆ setAt() [1/2]

◆ setAt() [2/2]

◆ setColumnName() [1/2]

◆ setColumnName() [2/2]

◆ setUnit()

◆ shape()

◆ unit()

◆ write()