tech.tablesaw.table

Class TableSlice

java.lang.Object

tech.tablesaw.table.Relation

tech.tablesaw.table.TableSlice

All Implemented Interfaces:

Iterable<Row>

public class TableSlice
extends Relation

A TableSlice is a facade around a Relation that acts as a filter. Requests for data are forwarded to the underlying table. A TableSlice can be sorted independently of the underlying table.

A TableSlice is only good until the structure of the underlying table changes.

Constructor Summary

Constructors

Constructor and Description
TableSlice(Table table) Returns a new view constructed from the given table.
TableSlice(Table table, Selection rowSelection) Returns a new View constructed from the given table, containing only the rows represented by the bitmap

Method Summary

Modifier and Type	Method and Description
TableSlice	addColumns(Column<?>... column)
Table	asTable()
void	clear() Clears all rows from this View, leaving the structure in place
Column<?>	column(int columnIndex) Returns the column at columnIndex (0-based)
Column<?>	column(String columnName) Returns the column with the given columnName, ignoring case
int	columnCount() Returns the number of columns in the relation
int	columnIndex(Column<?> column) Returns the index of the given column
List<String>	columnNames()
List<Column<?>>	columns() Returns a list of all the columns in the relation
Table	first(int nRows)
Object	get(int r, int c) Returns the value at the given row and column indexes
Table	getTable()
Iterator<Row>	iterator() Iterate over the underlying rows in the source table.
int	mappedRowNumber(int rowNumber) Maps the view row number to the row number on the underlying source table.
String	name() Returns the name of this relation
double	reduce(String numberColumnName, NumericAggregateFunction function) Returns the result of applying the given function to the specified column
TableSlice	removeColumns(Column<?>... columns) Removes the given columns from the receiver
void	removeSelection() Removes the selection from this view, leaving it with the same number of rows as the underlying source table.
void	removeSort() Removes the sort from this View.
int	rowCount() Returns the number of rows in the relation
TableSlice	setName(String name)
void	sortOn(Sort key) Sort this view in place without modifying or copying the underlying source table.
protected PrimitiveIterator.OfInt	sourceRowNumberIterator() IntIterator of source table row numbers that are present in this view.

Methods inherited from class tech.tablesaw.table.Relation

as, booleanColumn, booleanColumn, booleanColumns, categoricalColumn, categoricalColumn, categoricalColumns, columnIndex, columns, columns, columnsOfType, columnTypes, colWidths, containsColumn, dateColumn, dateColumn, dateColumns, dateTimeColumn, dateTimeColumn, dateTimeColumns, doubleColumn, doubleColumn, floatColumn, floatColumn, getString, getString, getUnformatted, instantColumn, instantColumn, instantColumns, intColumn, intColumn, isEmpty, longColumn, longColumn, nCol, nCol, numberColumn, numberColumn, numberColumns, numericColumns, numericColumns, numericColumns, print, print, printAll, removeColumns, removeColumns, shape, shortColumn, shortColumn, smile, stringColumn, stringColumn, stringColumns, structure, summary, textColumn, textColumn, timeColumn, timeColumn, timeColumns, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Constructor Detail

TableSlice

public TableSlice(Table table,
                  Selection rowSelection)

Returns a new View constructed from the given table, containing only the rows represented by the bitmap

TableSlice

public TableSlice(Table table)

Returns a new view constructed from the given table. The view can be sorted independently of the table.

Method Detail

column

public Column<?> column(int columnIndex)

Description copied from class: Relation

Returns the column at columnIndex (0-based)

Specified by:

column in class Relation

Parameters:

columnIndex - an integer at least 0 and less than number of columns in the relation

Returns:

the column at the given index

column

public Column<?> column(String columnName)

Description copied from class: Relation

Returns the column with the given columnName, ignoring case

Overrides:

column in class Relation

columnCount

public int columnCount()

Description copied from class: Relation

Returns the number of columns in the relation

Specified by:

columnCount in class Relation

rowCount

public int rowCount()

Description copied from class: Relation

Returns the number of rows in the relation

Specified by:

rowCount in class Relation

columns

public List<Column<?>> columns()

Description copied from class: Relation

Returns a list of all the columns in the relation

Specified by:

columns in class Relation

columnIndex

public int columnIndex(Column<?> column)

Description copied from class: Relation

Returns the index of the given column

Specified by:

columnIndex in class Relation

get

public Object get(int r,
                  int c)

Description copied from class: Relation

Returns the value at the given row and column indexes

Overrides:

get in class Relation

Parameters:

r - the row index, 0 based

c - the column index, 0 based

name

public String name()

Description copied from class: Relation

Returns the name of this relation

Specified by:

name in class Relation

getTable

public Table getTable()

clear

public void clear()

Clears all rows from this View, leaving the structure in place

Specified by:

clear in class Relation

removeSort

public void removeSort()

Removes the sort from this View.

removeSelection

public void removeSelection()

Removes the selection from this view, leaving it with the same number of rows as the underlying source table.

columnNames

public List<String> columnNames()

Specified by:

columnNames in class Relation

addColumns

public TableSlice addColumns(Column<?>... column)

Specified by:

addColumns in class Relation

removeColumns

public TableSlice removeColumns(Column<?>... columns)

Description copied from class: Relation

Removes the given columns from the receiver

Specified by:

removeColumns in class Relation

first

public Table first(int nRows)

Specified by:

first in class Relation

setName

public TableSlice setName(String name)

Specified by:

setName in class Relation

asTable

public Table asTable()

sourceRowNumberIterator

protected PrimitiveIterator.OfInt sourceRowNumberIterator()

IntIterator of source table row numbers that are present in this view. This can be used to in combination with the source table to iterate over the cells of a column in a sorted order without copying the column.

Returns:

an int iterator of row numbers in the source table that are present in this view.

reduce

public double reduce(String numberColumnName,
                     NumericAggregateFunction function)

Returns the result of applying the given function to the specified column

Parameters:

numberColumnName - The name of a numeric column in this table

function - A numeric reduce function

Returns:

the function result

Throws:

IllegalArgumentException - if numberColumnName doesn't name a numeric column in this table

iterator

public Iterator<Row> iterator()

Iterate over the underlying rows in the source table. If you set one of the rows while iterating it will change the row in the source table.

mappedRowNumber

public int mappedRowNumber(int rowNumber)

Maps the view row number to the row number on the underlying source table.

Parameters:

rowNumber - the row number in the view.

Returns:

the matching row number in the underlying table.

sortOn

public void sortOn(Sort key)

Sort this view in place without modifying or copying the underlying source table. Unlike Table.sortOn(Sort) which returns a copy of the table, this method sorts the view in place.

Parameters:

key - to sort on.