Package tech.tablesaw.api

Class Table

java.lang.Object

tech.tablesaw.table.Relation

tech.tablesaw.api.Table

All Implemented Interfaces:

Iterable<Row>

public class Table
extends Relation
implements Iterable<Row>

A table of data, consisting of some number of columns, each of which has the same number of rows. All the data in a column has the same type: integer, float, category, etc., but a table may contain an arbitrary number of columns of any type.

Tables are the main data-type and primary focus of Tablesaw.

Field Summary

Fields

Modifier and Type	Field	Description
static final ReaderRegistry	defaultReaderRegistry
static final WriterRegistry	defaultWriterRegistry
static final String	MELT_VALUE_COLUMN_NAME
static final String	MELT_VARIABLE_COLUMN_NAME

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	Table(String name, Collection<Column<?>> columns)	Returns a new Table initialized with the given names and columns
protected	Table(String name, Column<?>... columns)	Returns a new Table initialized with the given names and columns

Method Summary

Modifier and Type	Method	Description
Table	addColumns(Column<?>... cols)	Adds the given column to this table.
void	addRow(int rowIndex, Table sourceTable)	Adds a single row to this table from sourceTable, copying every column in sourceTable
Table	append(Row row)	Appends the given row to this table and returns the table.
Table	append(Relation tableToAppend)	Returns this table after adding the data from the argument
Row	appendRow()	Appends an empty row and returns a Row object indexed to the newly added row so values can be set.
Table	cast()	Cast implements the 'tidy' cast operation as described in these papers by Hadley Wickham:
List<CategoricalColumn<?>>	categoricalColumns(String... columnNames)	Returns only the columns whose names are given in the input array
void	clear()	Clears all the data from this table
Column<?>	column(int columnIndex)	Returns the column at the given index in the column list
Column<?>[]	columnArray()	Returns the columns in this table as an array
int	columnCount()	Returns the number of columns in the table
int	columnIndex(String columnName)	Returns the index of the column with the given name
int	columnIndex(Column<?> column)	Returns the index of the given column (its position in the list of columns)
List<String>	columnNames()	Returns a List of the names of all the columns in this table
List<Column<?>>	columns()	Returns the list of columns
static boolean	compareRows(int rowNumber, Table table1, Table table2)	Returns true if the row rowNumber in table1 holds the same values than the row at rowNumber in table2.
Table	concat(Table tableToConcatenate)	Add all the columns of tableToConcatenate to this table Note: The columns in the result must have unique names, when compared case insensitive Note: Both tables must have the same number of rows
Table	copy()	Returns a table with the same columns and data as this table
void	copyRowsToTable(int[] rows, Table newTable)	Copies the rows indicated by the row index values in the given array from oldTable to newTable
void	copyRowsToTable(Selection rows, Table newTable)	Copies the rows specified by Selection into newTable
Table	countBy(String... categoricalColumnNames)	Returns a table containing a column for each grouping column, and a column named "Count" that contains the counts for each combination of grouping column values
Table	countBy(CategoricalColumn<?>... groupingColumns)	Returns a table containing two columns, the grouping column, and a column named "Count" that contains the counts for each grouping column value
static Table	create()	Returns a new, empty table (without rows or columns)
static Table	create(String tableName)	Returns a new, empty table (without rows or columns) with the given name
static Table	create(String name, Collection<Column<?>> columns)	Returns a new table with the given columns and given name
static Table	create(String name, Stream<Column<?>> columns)	Returns a new table with the given columns and given name
static Table	create(String name, Column<?>... columns)	Returns a new table with the given columns and given name
static Table	create(Collection<Column<?>> columns)	Returns a new table with the given columns
static Table	create(Stream<Column<?>> columns)	Returns a new table with the given columns
static Table	create(Column<?>... columns)	Returns a new table with the given columns
Table	dropDuplicateRows()	Returns the unique records in this table, such that any record that appears more than once in this table, appears only once in the returned table.
Table	dropRange(int rowCount)	Returns a new table EXCLUDING the first rowCount rows if rowCount positive.
Table	dropRange(int rowStart, int rowEnd)	Returns a table EXCLUDING the rows contained in the range from rowStart inclusive to rowEnd exclusive
Table	dropRows(int... rowNumbers)	Returns a table EXCLUDING the rows contained in the given array of row indices
Table	dropRowsWithMissingValues()	Returns only those records in this table that have no columns with missing values
Table	dropWhere(Function<Table,Selection> selection)	Returns a new Table made by EXCLUDING any rows returned when the given function is applied to this table
Table	dropWhere(Selection selection)	Returns a table EXCLUDING the rows contained in the given Selection
Table	emptyCopy()	Returns a table with the same columns as this table, but no data
Table	emptyCopy(int rowSize)	Returns a table with the same columns as this table, but no data, initialized to the given row size
Table	first(int nRows)	Returns a new table containing the first nrows of data in this table
Table	inRange(int rowCount)	Returns a new table containing the first rowCount rows if rowCount positive.
Table	inRange(int rowStart, int rowEnd)	Returns a new table containing the rows contained in the range from rowStart inclusive to rowEnd exclusive
Table	insertColumn(int index, Column<?> column)	Adds the given column to this table at the given position in the column list.
void	internalAddWithoutValidation(Column<?> c)	For internal Tablesaw use only
Iterator<Row>	iterator()
DataFrameJoiner	joinOn(String... columnNames)	Returns a new DataFrameJoiner initialized with multiple columnNames
Table	last(int nRows)	Returns a new table containing the last nrows of data in this table
Table	melt(List<String> idVariables, List<NumericColumn<?>> measuredVariables, boolean dropMissing)	Melt implements the 'tidy' melt operation as described in these papers by Hadley Wickham.
Table	missingValueCounts()	Returns a table containing the number of missing values in each column in this table
String	name()	Returns the name of the table
Table	pivot(String column1Name, String column2Name, String column3Name, AggregateFunction<?,?> aggregateFunction)	Returns a pivot on this table, where: The first column contains unique values from the index column1 There are n additional columns, one for each unique value in column2 The values in each of the cells in these new columns are the result of applying the given AggregateFunction to the data in column3, grouped by the values of column1 and column2
Table	pivot(CategoricalColumn<?> column1, CategoricalColumn<?> column2, NumericColumn<?> column3, AggregateFunction<?,?> aggregateFunction)	Returns a pivot on this table, where: The first column contains unique values from the index column1 There are n additional columns, one for each unique value in column2 The values in each of the cells in these new columns are the result of applying the given AggregateFunction to the data in column3, grouped by the values of column1 and column2
static DataFrameReader	read()	Returns an object that an be used to read data from a file into a new Table
Table	rejectColumns(int... columnIndexes)	Returns a new table containing copies of all the columns from this table, except those at the given indexes
Table	rejectColumns(String... columnNames)	Returns a new table containing copies of all the columns from this table, except those named in the argument
Table	rejectColumns(Column<?>... columns)	Returns a new table containing copies of all the columns from this table, except those named in the argument
Table	removeColumns(int... columnIndexes)	Removes the columns at the given indices from this table and returns this table
Table	removeColumns(String... columns)	Removes the columns with the given names from this table and returns this table
Table	removeColumns(Column<?>... columns)	Removes the given columns from this table and returns this table
Table	removeColumnsWithMissingValues()	Removes all columns with missing values from this table, and returns this table.
Table	reorderColumns(String... columnNames)	Return a new table (shallow copy) that contains all the columns in this table, in the order given in the argument.
Table	replaceColumn(int colIndex, Column<?> newColumn)	Replaces an existing column (by index) in this table with the given new column
Table	replaceColumn(String columnName, Column<?> newColumn)	Replaces an existing column (by name) in this table with the given new column
Table	replaceColumn(Column<?> newColumn)	Replaces an existing column having the same name of the given column with the given column
Table	retainColumns(int... columnIndexes)	Removes all columns except for those given in the argument from this table and returns this table
Table	retainColumns(String... columnNames)	Removes all columns except for those given in the argument from this table and returns this table
Table	retainColumns(Column<?>... columns)	Removes all columns except for those given in the argument from this table and returns this table
Iterator<Row[]>	rollingIterator(int n)	Iterates over rolling sets of rows.
Stream<Row[]>	rollingStream(int n)	Streams over rolling sets of rows.
Row	row(int rowIndex)	Returns a new Row object with its position set to the given zero-based row index.
int	rowCount()	Returns the number of rows in the table
Table	rows(int... rowNumbers)	Returns a table containing the rows contained in the given array of row indices
Table	sampleN(int nRows)	Returns a table consisting of randomly selected records from this table
Table[]	sampleSplit(double table1Proportion)
Table	sampleX(double proportion)	Returns a table consisting of randomly selected records from this table.
Table	selectColumns(int... columnIndexes)	Returns a new table containing copies of the columns at the given indexes
Table	selectColumns(String... columnNames)	Returns a new table containing copies of the selected columns from this table
Table	selectColumns(Column<?>... columns)	Returns a new table containing copies of the selected columns from this table
Table	setName(String name)	Sets the name of the table
Table	sortAscendingOn(String... columnNames)	Returns a copy of this table sorted in the order of the given column names, in ascending order
Table	sortDescendingOn(String... columnNames)	Returns a copy of this table sorted on the given column names, applied in order, descending TODO: Provide equivalent methods naming columns by index
Table	sortOn(int... columnIndexes)	Sorts this table into a new table on the columns indexed
Table	sortOn(String... columnNames)	Returns a copy of this table sorted on the given column names, applied in order,
Table	sortOn(Comparator<Row> rowComparator)	Returns a copy of this table sorted using the given comparator
Table	sortOn(Sort key)	Returns a copy of this table sorted using the given sort key.
TableSliceGroup	splitOn(String... columns)	Returns a non-overlapping and exhaustive collection of "slices" over this table.
TableSliceGroup	splitOn(CategoricalColumn<?>... columns)	Returns a non-overlapping and exhaustive collection of "slices" over this table.
Iterator<Row[]>	steppingIterator(int n)	Streams over stepped sets of rows.
Stream<Row[]>	steppingStream(int n)	Streams over stepped sets of rows.
Table[]	stratifiedSampleSplit(CategoricalColumn<?> column, double table1Proportion)	Splits the table into two stratified samples, this uses the specified column to divide the table into groups, randomly assigning records to each according to the proportion given in trainingProportion.
Stream<Row>	stream()	Returns the rows in this table as a Stream
Summarizer	summarize(String col1Name, String col2Name, String col3Name, String col4Name, AggregateFunction<?,?>... functions)	Returns a Summarizer that can be used to summarize the column with the given name(s) using the given functions.
Summarizer	summarize(String col1Name, String col2Name, String col3Name, AggregateFunction<?,?>... functions)	Returns a Summarizer that can be used to summarize the column with the given name(s) using the given functions.
Summarizer	summarize(String numericColumn1Name, String numericColumn2Name, AggregateFunction<?,?>... functions)	Returns a Summarizer that can be used to summarize the column with the given name(s) using the given functions.
Summarizer	summarize(String columName, AggregateFunction<?,?>... functions)	Returns a Summarizer that can be used to summarize the column with the given name(s) using the given functions.
Summarizer	summarize(List<String> columnNames, AggregateFunction<?,?>... functions)	Returns a Summarizer that can be used to summarize the column with the given name(s) using the given functions.
Summarizer	summarize(Column<?> numberColumn, AggregateFunction<?,?>... function)	Returns a Summarizer that can be used to summarize the column with the given name(s) using the given functions.
Summarizer	summarize(Column<?> column1, Column<?> column2, AggregateFunction<?,?>... function)	Returns a Summarizer that can be used to summarize the column with the given name(s) using the given functions.
Summarizer	summarize(Column<?> column1, Column<?> column2, Column<?> column3, AggregateFunction<?,?>... function)	Returns a Summarizer that can be used to summarize the column with the given name(s) using the given functions.
Summarizer	summarize(Column<?> column1, Column<?> column2, Column<?> column3, Column<?> column4, AggregateFunction<?,?>... function)	Returns a Summarizer that can be used to summarize the column with the given name(s) using the given functions.
Table	transpose()	Transposes data in the table, switching rows for columns.
Table	transpose(boolean includeColumnHeadingsAsFirstColumn, boolean useFirstColumnForHeadings)	Transposes data in the table, switching rows for columns.
Table	where(Function<Table,Selection> selection)	Returns a new Table made by applying the given function to this table
Table	where(Selection selection)	Returns a table containing the rows contained in the given Selection
DataFrameWriter	write()	Returns an object that an be used to write data from a Table into a file.
Table	xTabColumnPercents(String column1Name, String column2Name)	Returns a table with n by m + 1 cells.
Table	xTabCounts(String column1Name)	Returns a table with two columns, the first contains a value each unique value in the argument, and the second contains the number of observations of each value
Table	xTabCounts(String column1Name, String column2Name)	Returns a table with n by m + 1 cells.
Table	xTabPercents(String column1Name)	TODO: Rename the method to xTabProportions, deprecating this version Returns a table with two columns, the first contains a value each unique value in the argument, and the second contains the proportion of observations having that value
Table	xTabRowPercents(String column1Name, String column2Name)	Returns a table with n by m + 1 cells.
Table	xTabTablePercents(String column1Name, String column2Name)	Returns a table with n by m + 1 cells.

Methods inherited from class tech.tablesaw.table.Relation

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

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

Field Details

defaultReaderRegistry

public static final ReaderRegistry defaultReaderRegistry

defaultWriterRegistry

public static final WriterRegistry defaultWriterRegistry

MELT_VARIABLE_COLUMN_NAME

public static final String MELT_VARIABLE_COLUMN_NAME

See Also:

• Constant Field Values

MELT_VALUE_COLUMN_NAME

public static final String MELT_VALUE_COLUMN_NAME

See Also:

• Constant Field Values

Constructor Details

Table

protected Table(String name,
 Column<?>... columns)

Returns a new Table initialized with the given names and columns

Parameters:

name - The name of the table

columns - One or more columns, all of which must have either the same length or size 0

Table

protected Table(String name,
 Collection<Column<?>> columns)

Returns a new Table initialized with the given names and columns

Parameters:

name - The name of the table

columns - One or more columns, all of which must have either the same length or size 0

Method Details

create

public static Table create()

Returns a new, empty table (without rows or columns)

create

public static Table create(String tableName)

Returns a new, empty table (without rows or columns) with the given name

create

public static Table create(Column<?>... columns)

Returns a new table with the given columns

Parameters:

columns - one or more columns, all of the same @code{column.size()}

create

public static Table create(Collection<Column<?>> columns)

Returns a new table with the given columns

Parameters:

columns - one or more columns, all of the same @code{column.size()}

create

public static Table create(Stream<Column<?>> columns)

Returns a new table with the given columns

Parameters:

columns - one or more columns, all of the same @code{column.size()}

create

public static Table create(String name,
 Column<?>... columns)

Returns a new table with the given columns and given name

Parameters:

name - the name for this table

columns - one or more columns, all of the same @code{column.size()}

create

public static Table create(String name,
 Collection<Column<?>> columns)

Returns a new table with the given columns and given name

Parameters:

name - the name for this table

columns - one or more columns, all of the same @code{column.size()}

create

public static Table create(String name,
 Stream<Column<?>> columns)

Returns a new table with the given columns and given name

Parameters:

name - the name for this table

columns - one or more columns, all of the same @code{column.size()}

read

public static DataFrameReader read()

Returns an object that an be used to read data from a file into a new Table

write

public DataFrameWriter write()

Returns an object that an be used to write data from a Table into a file. If the file exists, it is over-written

addColumns

public Table addColumns(Column<?>... cols)

Adds the given column to this table. Column must either be empty or have size() == the rowCount() of the table they're being added to. Column names in the table must remain unique.

Specified by:

addColumns in class Relation

Returns:

This Relation

internalAddWithoutValidation

public void internalAddWithoutValidation(Column<?> c)

For internal Tablesaw use only

Adds the given column to this table without performing duplicate-name or column size checks

insertColumn

public Table insertColumn(int index,
 Column<?> column)

Adds the given column to this table at the given position in the column list. Columns must either be empty or have size() == the rowCount() of the table they're being added to. Column names in the table must remain unique.

Parameters:

index - Zero-based index into the column list

column - Column to be added

reorderColumns

public Table reorderColumns(String... columnNames)

Return a new table (shallow copy) that contains all the columns in this table, in the order given in the argument. Throw an IllegalArgument exception if the number of names given does not match the number of columns in this table. NOTE: This does not make a copy of the columns, so they are shared between the two tables.

Parameters:

columnNames - a column name or array of names

replaceColumn

public Table replaceColumn(int colIndex,
 Column<?> newColumn)

Replaces an existing column (by index) in this table with the given new column

Parameters:

colIndex - Zero-based index of the column to be replaced

newColumn - Column to be added

replaceColumn

public Table replaceColumn(String columnName,
 Column<?> newColumn)

Replaces an existing column (by name) in this table with the given new column

Parameters:

columnName - String name of the column to be replaced

newColumn - Column to be added

replaceColumn

public Table replaceColumn(Column<?> newColumn)

Replaces an existing column having the same name of the given column with the given column

Parameters:

newColumn - Column to be added

setName

public Table setName(String name)

Sets the name of the table

Specified by:

setName in class Relation

Returns:

This Relation

column

public Column<?> column(int columnIndex)

Returns the column at the given index in the column list

Specified by:

column in class Relation

Parameters:

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

Returns:

the column at the given index

columnCount

public int columnCount()

Returns the number of columns in the table

Specified by:

columnCount in class Relation

rowCount

public int rowCount()

Returns the number of rows in the table

Specified by:

rowCount in class Relation

columns

public List<Column<?>> columns()

Returns the list of columns

Specified by:

columns in class Relation

columnArray

public Column<?>[] columnArray()

Returns the columns in this table as an array

categoricalColumns

public List<CategoricalColumn<?>> categoricalColumns(String... columnNames)

Returns only the columns whose names are given in the input array

Overrides:

categoricalColumns in class Relation

columnIndex

public int columnIndex(String columnName)

Returns the index of the column with the given name

Overrides:

columnIndex in class Relation

Throws:

IllegalArgumentException - if the input string is not the name of any column in the table

columnIndex

public int columnIndex(Column<?> column)

Returns the index of the given column (its position in the list of columns)

Specified by:

columnIndex in class Relation

Throws:

IllegalArgumentException - if the column is not present in this table

name

public String name()

Returns the name of the table

Specified by:

name in class Relation

columnNames

public List<String> columnNames()

Returns a List of the names of all the columns in this table

Specified by:

columnNames in class Relation

copy

public Table copy()

Returns a table with the same columns and data as this table

emptyCopy

public Table emptyCopy()

Returns a table with the same columns as this table, but no data

emptyCopy

public Table emptyCopy(int rowSize)

Returns a table with the same columns as this table, but no data, initialized to the given row size

copyRowsToTable

public void copyRowsToTable(Selection rows,
 Table newTable)

Copies the rows specified by Selection into newTable

Parameters:

rows - A Selection defining the rows to copy

newTable - The table to copy the rows into

copyRowsToTable

public void copyRowsToTable(int[] rows,
 Table newTable)

Copies the rows indicated by the row index values in the given array from oldTable to newTable

compareRows

public static boolean compareRows(int rowNumber,
 Table table1,
 Table table2)

Returns true if the row rowNumber in table1 holds the same values than the row at rowNumber in table2. Returns false if the number of columns is different in the two tables.

Parameters:

rowNumber - the row to compare

table1 - the first table to compare

table2 - the second table to compare

Returns:

false if row rowNumber is different in table1 and table2

sampleSplit

public Table[] sampleSplit(double table1Proportion)

stratifiedSampleSplit

public Table[] stratifiedSampleSplit(CategoricalColumn<?> column,
 double table1Proportion)

Splits the table into two stratified samples, this uses the specified column to divide the table into groups, randomly assigning records to each according to the proportion given in trainingProportion.

Parameters:

column - the column to be used for the stratified sampling

table1Proportion - The proportion to go in the first table

Returns:

An array two tables, with the first table having the proportion specified in the method parameter, and the second table having the balance of the rows

sampleX

public Table sampleX(double proportion)

Returns a table consisting of randomly selected records from this table. The sample size is based on the given proportion

Parameters:

proportion - The proportion to go in the sample

sampleN

public Table sampleN(int nRows)

Returns a table consisting of randomly selected records from this table

Parameters:

nRows - The number of rows to go in the sample

clear

public void clear()

Clears all the data from this table

Specified by:

clear in class Relation

first

public Table first(int nRows)

Returns a new table containing the first nrows of data in this table

Specified by:

first in class Relation

last

public Table last(int nRows)

Returns a new table containing the last nrows of data in this table

sortOn

public Table sortOn(int... columnIndexes)

Sorts this table into a new table on the columns indexed

if index is negative then sort that column in descending order otherwise sort ascending

sortOn

public Table sortOn(String... columnNames)

Returns a copy of this table sorted on the given column names, applied in order,

if column name starts with - then sort that column descending otherwise sort ascending

sortAscendingOn

public Table sortAscendingOn(String... columnNames)

Returns a copy of this table sorted in the order of the given column names, in ascending order

sortDescendingOn

public Table sortDescendingOn(String... columnNames)

Returns a copy of this table sorted on the given column names, applied in order, descending TODO: Provide equivalent methods naming columns by index

sortOn

public Table sortOn(Sort key)

Returns a copy of this table sorted using the given sort key.

Parameters:

key - to sort on.

Returns:

a sorted copy of this table.

sortOn

public Table sortOn(Comparator<Row> rowComparator)

Returns a copy of this table sorted using the given comparator

addRow

public void addRow(int rowIndex,
 Table sourceTable)

Adds a single row to this table from sourceTable, copying every column in sourceTable

Parameters:

rowIndex - The row in sourceTable to add to this table

sourceTable - A table with the same column structure as this table

row

public Row row(int rowIndex)

Returns a new Row object with its position set to the given zero-based row index.

rows

public Table rows(int... rowNumbers)

Returns a table containing the rows contained in the given array of row indices

dropRows

public Table dropRows(int... rowNumbers)

Returns a table EXCLUDING the rows contained in the given array of row indices

inRange

public Table inRange(int rowCount)

Returns a new table containing the first rowCount rows if rowCount positive. Returns the last rowCount rows if rowCount negative.

inRange

public Table inRange(int rowStart,
 int rowEnd)

Returns a new table containing the rows contained in the range from rowStart inclusive to rowEnd exclusive

dropRange

public Table dropRange(int rowCount)

Returns a new table EXCLUDING the first rowCount rows if rowCount positive. Drops the last rowCount rows if rowCount negative.

dropRange

public Table dropRange(int rowStart,
 int rowEnd)

Returns a table EXCLUDING the rows contained in the range from rowStart inclusive to rowEnd exclusive

where

public Table where(Selection selection)

Returns a table containing the rows contained in the given Selection

where

public Table where(Function<Table,Selection> selection)

Returns a new Table made by applying the given function to this table

dropWhere

public Table dropWhere(Function<Table,Selection> selection)

Returns a new Table made by EXCLUDING any rows returned when the given function is applied to this table

dropWhere

public Table dropWhere(Selection selection)

Returns a table EXCLUDING the rows contained in the given Selection

pivot

public Table pivot(CategoricalColumn<?> column1,
 CategoricalColumn<?> column2,
 NumericColumn<?> column3,
 AggregateFunction<?,?> aggregateFunction)

Returns a pivot on this table, where: The first column contains unique values from the index column1 There are n additional columns, one for each unique value in column2 The values in each of the cells in these new columns are the result of applying the given AggregateFunction to the data in column3, grouped by the values of column1 and column2

pivot

public Table pivot(String column1Name,
 String column2Name,
 String column3Name,
 AggregateFunction<?,?> aggregateFunction)

Returns a pivot on this table, where: The first column contains unique values from the index column1 There are n additional columns, one for each unique value in column2 The values in each of the cells in these new columns are the result of applying the given AggregateFunction to the data in column3, grouped by the values of column1 and column2

splitOn

public TableSliceGroup splitOn(String... columns)

Returns a non-overlapping and exhaustive collection of "slices" over this table. Each slice is like a virtual table containing a subset of the records in this table

This method is intended for advanced or unusual operations on the subtables. If you want to calculate summary statistics for each subtable, the summarize methods (e.g)

table.summarize(myColumn, mean, median).by(columns)

are preferred

splitOn

public TableSliceGroup splitOn(CategoricalColumn<?>... columns)

Returns a non-overlapping and exhaustive collection of "slices" over this table. Each slice is like a virtual table containing a subset of the records in this table

This method is intended for advanced or unusual operations on the subtables. If you want to calculate summary statistics for each subtable, the summarize methods (e.g)

table.summarize(myColumn, mean, median).by(columns)

are preferred

dropDuplicateRows

public Table dropDuplicateRows()

Returns the unique records in this table, such that any record that appears more than once in this table, appears only once in the returned table.

dropRowsWithMissingValues

public Table dropRowsWithMissingValues()

Returns only those records in this table that have no columns with missing values

selectColumns

public Table selectColumns(Column<?>... columns)

Returns a new table containing copies of the selected columns from this table

Parameters:

columns - The columns to copy into the new table

See Also:

• retainColumns(Column[])

selectColumns

public Table selectColumns(String... columnNames)

Returns a new table containing copies of the selected columns from this table

Parameters:

columnNames - The names of the columns to include

See Also:

• retainColumns(String[])

rejectColumns

public Table rejectColumns(int... columnIndexes)

Returns a new table containing copies of all the columns from this table, except those at the given indexes

Parameters:

columnIndexes - The indexes of the columns to exclude

See Also:

• removeColumns(int[])

rejectColumns

public Table rejectColumns(String... columnNames)

Returns a new table containing copies of all the columns from this table, except those named in the argument

Parameters:

columnNames - The names of the columns to exclude

See Also:

• removeColumns(int[])

rejectColumns

public Table rejectColumns(Column<?>... columns)

Returns a new table containing copies of all the columns from this table, except those named in the argument

Parameters:

columns - The names of the columns to exclude

See Also:

• removeColumns(int[])

selectColumns

public Table selectColumns(int... columnIndexes)

Returns a new table containing copies of the columns at the given indexes

Parameters:

columnIndexes - The indexes of the columns to include

See Also:

• retainColumns(int[])

removeColumns

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

Removes the given columns from this table and returns this table

Specified by:

removeColumns in class Relation

Returns:

This Relation

removeColumnsWithMissingValues

public Table removeColumnsWithMissingValues()

Removes all columns with missing values from this table, and returns this table.

retainColumns

public Table retainColumns(Column<?>... columns)

Removes all columns except for those given in the argument from this table and returns this table

retainColumns

public Table retainColumns(int... columnIndexes)

Removes all columns except for those given in the argument from this table and returns this table

retainColumns

public Table retainColumns(String... columnNames)

Removes all columns except for those given in the argument from this table and returns this table

append

public Table append(Relation tableToAppend)

Returns this table after adding the data from the argument

append

public Table append(Row row)

Appends the given row to this table and returns the table.

Note: The table is modified in-place TODO: Performance

removeColumns

public Table removeColumns(String... columns)

Removes the columns with the given names from this table and returns this table

Overrides:

removeColumns in class Relation

Returns:

This Relation

removeColumns

public Table removeColumns(int... columnIndexes)

Removes the columns at the given indices from this table and returns this table

Overrides:

removeColumns in class Relation

Returns:

This Relation

appendRow

public Row appendRow()

Appends an empty row and returns a Row object indexed to the newly added row so values can be set.

Intended usage:

for (int i = 0; ...) { Row row = table.appendRow(); row.setString("name", "Bob"); row.setFloat("IQ", 123.4f); ...etc. }

concat

public Table concat(Table tableToConcatenate)

Add all the columns of tableToConcatenate to this table Note: The columns in the result must have unique names, when compared case insensitive Note: Both tables must have the same number of rows

Parameters:

tableToConcatenate - The table containing the columns to be added

Returns:

This table

summarize

public Summarizer summarize(String columName,
 AggregateFunction<?,?>... functions)

Returns a Summarizer that can be used to summarize the column with the given name(s) using the given functions. This object implements reduce/aggregation operations on a table.

Summarizer can return the results as a table using the Summarizer:apply() method. Summarizer can compute sub-totals using the Summarizer:by() method.

summarize

public Summarizer summarize(List<String> columnNames,
 AggregateFunction<?,?>... functions)

Returns a Summarizer that can be used to summarize the column with the given name(s) using the given functions. This object implements reduce/aggregation operations on a table.

Summarizer can return the results as a table using the Summarizer:apply() method. Summarizer can compute sub-totals using the Summarizer:by() method.

summarize

public Summarizer summarize(String numericColumn1Name,
 String numericColumn2Name,
 AggregateFunction<?,?>... functions)

Returns a Summarizer that can be used to summarize the column with the given name(s) using the given functions. This object implements reduce/aggregation operations on a table.

Summarizer can return the results as a table using the Summarizer:apply() method. Summarizer can compute sub-totals using the Summarizer:by() method.

summarize

public Summarizer summarize(String col1Name,
 String col2Name,
 String col3Name,
 AggregateFunction<?,?>... functions)

Returns a Summarizer that can be used to summarize the column with the given name(s) using the given functions. This object implements reduce/aggregation operations on a table.

Summarizer can return the results as a table using the Summarizer:apply() method. Summarizer can compute sub-totals using the Summarizer:by() method.

summarize

public Summarizer summarize(String col1Name,
 String col2Name,
 String col3Name,
 String col4Name,
 AggregateFunction<?,?>... functions)

Returns a Summarizer that can be used to summarize the column with the given name(s) using the given functions. This object implements reduce/aggregation operations on a table.

Summarizer can return the results as a table using the Summarizer:apply() method. Summarizer can compute sub-totals using the Summarizer:by() method.

summarize

public Summarizer summarize(Column<?> numberColumn,
 AggregateFunction<?,?>... function)

Returns a Summarizer that can be used to summarize the column with the given name(s) using the given functions. This object implements reduce/aggregation operations on a table.

Summarizer can return the results as a table using the Summarizer:apply() method. Summarizer can compute sub-totals using the Summarizer:by() method.

summarize

public Summarizer summarize(Column<?> column1,
 Column<?> column2,
 AggregateFunction<?,?>... function)

Returns a Summarizer that can be used to summarize the column with the given name(s) using the given functions. This object implements reduce/aggregation operations on a table.

Summarizer can return the results as a table using the Summarizer:apply() method. Summarizer can compute sub-totals using the Summarizer:by() method.

summarize

public Summarizer summarize(Column<?> column1,
 Column<?> column2,
 Column<?> column3,
 AggregateFunction<?,?>... function)

Returns a Summarizer that can be used to summarize the column with the given name(s) using the given functions. This object implements reduce/aggregation operations on a table.

Summarizer can return the results as a table using the Summarizer:apply() method. Summarizer can compute sub-totals using the Summarizer:by() method.

summarize

public Summarizer summarize(Column<?> column1,
 Column<?> column2,
 Column<?> column3,
 Column<?> column4,
 AggregateFunction<?,?>... function)

Returns a Summarizer that can be used to summarize the column with the given name(s) using the given functions. This object implements reduce/aggregation operations on a table.

Summarizer can return the results as a table using the Summarizer:apply() method. Summarizer can compute sub-totals using the Summarizer:by() method.

xTabCounts

public Table xTabCounts(String column1Name,
 String column2Name)

Returns a table with n by m + 1 cells. The first column contains labels, the other cells contains the counts for every unique combination of values from the two specified columns in this table.

xTabRowPercents

public Table xTabRowPercents(String column1Name,
 String column2Name)

Returns a table with n by m + 1 cells. The first column contains labels, the other cells contains the row percents for every unique combination of values from the two specified columns in this table. Row percents total to 100% in every row.

xTabColumnPercents

public Table xTabColumnPercents(String column1Name,
 String column2Name)

Returns a table with n by m + 1 cells. The first column contains labels, the other cells contains the column percents for every unique combination of values from the two specified columns in this table. Column percents total to 100% in every column.

xTabTablePercents

public Table xTabTablePercents(String column1Name,
 String column2Name)

Returns a table with n by m + 1 cells. The first column contains labels, the other cells contains the proportion for a unique combination of values from the two specified columns in this table

xTabPercents

public Table xTabPercents(String column1Name)

TODO: Rename the method to xTabProportions, deprecating this version Returns a table with two columns, the first contains a value each unique value in the argument, and the second contains the proportion of observations having that value

xTabCounts

public Table xTabCounts(String column1Name)

Returns a table with two columns, the first contains a value each unique value in the argument, and the second contains the number of observations of each value

countBy

public Table countBy(CategoricalColumn<?>... groupingColumns)

Returns a table containing two columns, the grouping column, and a column named "Count" that contains the counts for each grouping column value

countBy

public Table countBy(String... categoricalColumnNames)

Returns a table containing a column for each grouping column, and a column named "Count" that contains the counts for each combination of grouping column values

Parameters:

categoricalColumnNames - The name(s) of one or more CategoricalColumns in this table

Returns:

A table containing counts of rows grouped by the categorical columns

Throws:

ClassCastException - if the categoricalColumnName parameter is the name of a column that does not * implement categorical

joinOn

public DataFrameJoiner joinOn(String... columnNames)

Returns a new DataFrameJoiner initialized with multiple columnNames

Parameters:

columnNames - Name of the columns to join on.

Returns:

The new DataFrameJoiner

missingValueCounts

public Table missingValueCounts()

Returns a table containing the number of missing values in each column in this table

iterator

public Iterator<Row> iterator()

Specified by:

iterator in interface Iterable<Row>

rollingIterator

public Iterator<Row[]> rollingIterator(int n)

Iterates over rolling sets of rows. I.e. 0 to n-1, 1 to n, 2 to n+1, etc.

Parameters:

n - the number of rows to return for each iteration

steppingIterator

public Iterator<Row[]> steppingIterator(int n)

Streams over stepped sets of rows. I.e. 0 to n-1, n to 2n-1, 2n to 3n-1, etc. Only returns full sets of rows.

Parameters:

n - the number of rows to return for each iteration

stream

public Stream<Row> stream()

Returns the rows in this table as a Stream

steppingStream

public Stream<Row[]> steppingStream(int n)

Streams over stepped sets of rows. I.e. 0 to n-1, n to 2n-1, 2n to 3n-1, etc. Only returns full sets of rows.

Parameters:

n - the number of rows to return for each iteration

rollingStream

public Stream<Row[]> rollingStream(int n)

Streams over rolling sets of rows. I.e. 0 to n-1, 1 to n, 2 to n+1, etc.

Parameters:

n - the number of rows to return for each iteration

transpose

public Table transpose()

Transposes data in the table, switching rows for columns. For example, a table like this.
value1 | value2 |
-------------------------------
1 | 2 |
1.1 | 2.1 |
1.2 | 2.2 |

Is transposed into the following
0 | 1 | 2 |
-------------------------------------
1 | 1.1 | 1.2 |
2 | 2.1 | 2.2 |

Returns:

transposed table

See Also:

• transpose(boolean,boolean)

transpose

public Table transpose(boolean includeColumnHeadingsAsFirstColumn,
 boolean useFirstColumnForHeadings)

Transposes data in the table, switching rows for columns. For example, a table like this.
label | value1 | value2 |
-------------------------------
row1 | 1 | 2 |
row2 | 1.1 | 2.1 |
row3 | 1.2 | 2.2 |

Is transposed into the following
label | row1 | row2 | row3 |
-------------------------------------
value1 | 1 | 1.1 | 1.2 |
value2 | 2 | 2.1 | 2.2 |

Parameters:

includeColumnHeadingsAsFirstColumn - Toggle whether to include the column headings as first column in result

useFirstColumnForHeadings - Use the first column as the column headings in the result. Useful if the data set already has a first column which contains a set of labels

Returns:

The transposed table

melt

public Table melt(List<String> idVariables,
 List<NumericColumn<?>> measuredVariables,
 boolean dropMissing)

Melt implements the 'tidy' melt operation as described in these papers by Hadley Wickham.

Tidy concepts: see https://www.jstatsoft.org/article/view/v059i10

Cast function details: see https://www.jstatsoft.org/article/view/v021i12

In short, melt turns columns into rows, but in a particular way. Used with the cast method, it can help make data tidy. In a tidy dataset, every variable is a column and every observation a row.

This method returns a table that contains all the data in this table, but organized such that there is a set of identifier variables (columns) and a single measured variable (column). For example, given a table with columns:

patient_id, gender, age, weight, temperature,

it returns a table with the columns:

patient_id, variable, value

In the new format, the strings age, weight, and temperature have become cells in the measurement table, such that a single row in the source table might look like this in the result table:

1234, gender, male 1234, age, 42 1234, weight, 186 1234, temperature, 97.4

This kind of structure often makes for a good intermediate format for performing subsequent transformations. It is especially useful when combined with the cast() operation

Parameters:

idVariables - A list of column names intended to be used as identifiers. In the example, only patient_id would be an identifier

measuredVariables - A list of columns intended to be used as measured variables. All columns must have the same type

dropMissing - drop any row where the value is missing

cast

public Table cast()

Cast implements the 'tidy' cast operation as described in these papers by Hadley Wickham:

Cast takes a table in 'molten' format, such as is produced by the #melt(List, List, Boolean) t} method, and returns a version in standard tidy format.

The molten table should have a StringColumn called "variable" and a column called "value" Every unique variable name will become a column in the output table.

All other columns in this table are considered identifier variable. Each combination of identifier variables specifies an observation, so there will be one row for each, with the other variables added.

Variable columns are returned in an arbitrary order. Use reorderColumns(String...) if column order is important.

Tidy concepts: see https://www.jstatsoft.org/article/view/v059i10

Cast function details: see https://www.jstatsoft.org/article/view/v021i12