Relation (tablesaw-core 0.40.0 API)

java.lang.Object
- tech.tablesaw.table.Relation

All Implemented Interfaces:

Iterable<Row>

Direct Known Subclasses:

Table, TableSlice
```
public abstract class Relation
extends Object
implements Iterable<Row>
```
A tabular data structure like a table in a relational database, but not formally implementing the relational algebra

Constructor Summary

Constructors
Constructor Description

Relation()

Constructors
Constructor	Description
`Relation()`

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods Deprecated Methods
Modifier and Type	Method	Description
`abstract Relation`	`addColumns(Column<?>... cols)`
`TableConverter`	`as()`
`BooleanColumn`	`booleanColumn(int columnIndex)`
`BooleanColumn`	`booleanColumn(String columnName)`
`BooleanColumn[]`	`booleanColumns()`
`CategoricalColumn<?>`	`categoricalColumn(int columnNumber)`
`CategoricalColumn<?>`	`categoricalColumn(String columnName)`
`List<CategoricalColumn<?>>`	`categoricalColumns(String... columnName)`	Returns the columns whose names are given in the input array
`abstract void`	`clear()`	Clears all the dat in the relation, leaving the structure intact
`abstract Column<?>`	`column(int columnIndex)`	Returns the column at columnIndex (0-based)
`Column<?>`	`column(String columnName)`	Returns the column with the given columnName, ignoring case
`abstract int`	`columnCount()`	Returns the number of columns in the relation
`int`	`columnIndex(String columnName)`	Returns the index of the column with the given columnName
`abstract int`	`columnIndex(Column<?> col)`	Returns the index of the given column
`abstract List<String>`	`columnNames()`
`abstract List<Column<?>>`	`columns()`	Returns a list of all the columns in the relation
`List<Column<?>>`	`columns(int... columnIndices)`	Returns the columns whose indices are given in the input array
`List<Column<?>>`	`columns(String... columnName)`	Returns the columns whose names are given in the input array
`List<Column<?>>`	`columnsOfType(ColumnType type)`
`ColumnType[]`	`columnTypes()`	Deprecated. for API name consistency. Use `typeArray()` instead.
`int[]`	`colWidths()`	Returns an array of column widths for printing tables
`boolean`	`containsColumn(String columnName)`
`boolean`	`containsColumn(Column<?> column)`
`DateColumn`	`dateColumn(int columnIndex)`
`DateColumn`	`dateColumn(String columnName)`
`DateColumn[]`	`dateColumns()`
`DateTimeColumn`	`dateTimeColumn(int columnIndex)`
`DateTimeColumn`	`dateTimeColumn(String columnName)`
`DateTimeColumn[]`	`dateTimeColumns()`
`DoubleColumn`	`doubleColumn(int columnIndex)`
`DoubleColumn`	`doubleColumn(String columnName)`
`abstract Table`	`first(int nRows)`
`FloatColumn`	`floatColumn(int columnIndex)`
`FloatColumn`	`floatColumn(String columnName)`
`Object`	`get(int r, int c)`	Returns the value at the given row and column indexes
`String`	`getString(int r, int columnIndex)`	Returns a string representation of the value at the given row and column indexes
`String`	`getString(int r, String columnName)`	Returns a string representation of the value at the given row and column indexes
`String`	`getUnformatted(int r, int c)`	Returns a string representation of the value at the given row and column indexes
`InstantColumn`	`instantColumn(int columnIndex)`
`InstantColumn`	`instantColumn(String columnName)`
`InstantColumn[]`	`instantColumns()`
`IntColumn`	`intColumn(int columnIndex)`
`IntColumn`	`intColumn(String columnName)`
`boolean`	`isEmpty()`
`LongColumn`	`longColumn(int columnIndex)`
`LongColumn`	`longColumn(String columnName)`
`abstract String`	`name()`	Returns the name of this relation
`NumericColumn<?>`	`nCol(int columnIndex)`	Returns the column with the given name cast to a NumberColumn
`NumericColumn<?>`	`nCol(String columnName)`	Returns the column with the given name cast to a NumberColumn
`NumericColumn<?>`	`numberColumn(int columnIndex)`	Returns the NumberColumn at the given index.
`NumericColumn<?>`	`numberColumn(String columnName)`
`NumericColumn<?>[]`	`numberColumns()`
`List<NumericColumn<?>>`	`numericColumns()`	Returns all the NumericColumns in the relation
`List<NumericColumn<?>>`	`numericColumns(int... columnIndices)`	Returns all the NumericColumns in the relation
`List<NumericColumn<?>>`	`numericColumns(String... columnNames)`	Returns all the NumericColumns in the relation
`String`	`print()`	Returns a String containing a 'pretty-printed' representation of this table containing at most 20 rows.
`String`	`print(int rowLimit)`
`String`	`printAll()`
`Relation`	`removeColumns(int... columnIndexes)`
`Relation`	`removeColumns(String... columnName)`
`abstract Relation`	`removeColumns(Column<?>... columns)`	Removes the given columns from the receiver
`abstract int`	`rowCount()`	Returns the number of rows in the relation
`abstract Relation`	`setName(String name)`
`String`	`shape()`
`ShortColumn`	`shortColumn(int columnIndex)`
`ShortColumn`	`shortColumn(String columnName)`
`SmileConverter`	`smile()`
`StringColumn`	`stringColumn(int columnIndex)`
`StringColumn`	`stringColumn(String columnName)`
`StringColumn[]`	`stringColumns()`
`Table`	`structure()`	Returns the structure of the this relation as a 3-column Table, consisting of Index (an IntColumn), Column Name (a StringColumn), and Column Type (a StringColumn)
`Table`	`summary()`
`TextColumn`	`textColumn(int columnIndex)`
`TextColumn`	`textColumn(String columnName)`
`TimeColumn`	`timeColumn(int columnIndex)`
`TimeColumn`	`timeColumn(String columnName)`
`TimeColumn[]`	`timeColumns()`
`String`	`toString()`	Returns a String containing a 'pretty-printed' representation of this table containing at most 20 rows.
`ColumnType[]`	`typeArray()`	Returns an array of the column types of all columns in the relation, including duplicates as appropriate, and maintaining order
`List<ColumnType>`	`types()`	Returns a List of the column types of all columns in the relation, including duplicates as appropriate, and maintaining order

Methods inherited from interface java.lang.Iterable
forEach, iterator, spliterator

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail
- Relation
```
public Relation()
```

Method Detail

addColumns

public abstract Relation addColumns(Column<?>... cols)

setName

public abstract Relation setName(String name)

isEmpty
```
public boolean isEmpty()
```

shape
```
public String shape()
```

removeColumns

public Relation removeColumns(int... columnIndexes)

removeColumns

public abstract Relation removeColumns(Column<?>... columns)

Removes the given columns from the receiver

removeColumns

public Relation removeColumns(String... columnName)

columnsOfType

public List<Column<?>> columnsOfType(ColumnType type)

first

public abstract Table first(int nRows)

columnIndex
```
public int columnIndex(String columnName)
```
Returns the index of the column with the given columnName

column
```
public Column<?> column(String columnName)
```
Returns the column with the given columnName, ignoring case

column
```
public abstract Column<?> column(int columnIndex)
```
Returns the column at columnIndex (0-based)

Parameters:

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

Returns:

the column at the given index

columnCount
```
public abstract int columnCount()
```
Returns the number of columns in the relation

rowCount
```
public abstract int rowCount()
```
Returns the number of rows in the relation

columns
```
public abstract List<Column<?>> columns()
```
Returns a list of all the columns in the relation

columns
```
public List<Column<?>> columns(String... columnName)
```
Returns the columns whose names are given in the input array

columns
```
public List<Column<?>> columns(int... columnIndices)
```
Returns the columns whose indices are given in the input array

columnIndex

public abstract int columnIndex(Column<?> col)

Returns the index of the given column

get
```
public Object get(int r,
                  int c)
```
Returns the value at the given row and column indexes

Parameters:

r - the row index, 0 based

c - the column index, 0 based

name
```
public abstract String name()
```
Returns the name of this relation

clear
```
public abstract void clear()
```
Clears all the dat in the relation, leaving the structure intact

columnNames

public abstract List<String> columnNames()

columnTypes
```
@Deprecated
public ColumnType[] columnTypes()
```
Deprecated. for API name consistency. Use typeArray() instead.

Returns an array of the column types of all columns in the relation, including duplicates as appropriate, and maintaining order

typeArray
```
public ColumnType[] typeArray()
```
Returns an array of the column types of all columns in the relation, including duplicates as appropriate, and maintaining order

types
```
public List<ColumnType> types()
```
Returns a List of the column types of all columns in the relation, including duplicates as appropriate, and maintaining order

colWidths
```
public int[] colWidths()
```
Returns an array of column widths for printing tables

toString
```
public String toString()
```
Returns a String containing a 'pretty-printed' representation of this table containing at most 20 rows. The 20 rows are the first and last ten in this table.

Overrides:

toString in class Object

printAll
```
public String printAll()
```

print
```
public String print(int rowLimit)
```

print
```
public String print()
```
Returns a String containing a 'pretty-printed' representation of this table containing at most 20 rows. The 20 rows are the first and last ten in this table.

structure
```
public Table structure()
```
Returns the structure of the this relation as a 3-column Table, consisting of Index (an IntColumn), Column Name (a StringColumn), and Column Type (a StringColumn)

summary
```
public Table summary()
```

booleanColumn

public BooleanColumn booleanColumn(int columnIndex)

booleanColumn

public BooleanColumn booleanColumn(String columnName)

numberColumn
```
public NumericColumn<?> numberColumn(int columnIndex)
```
Returns the NumberColumn at the given index. If the index points to a String or a boolean column, a new NumberColumn is created and returned TODO(lwhite):Consider separating the indexed access and the column type mods, which must be for ML functions (in smile or elsewhere)

Parameters:

columnIndex - The 0-based index of a column in the table

Returns:

A number column

Throws:

ClassCastException - if the cast to NumberColumn fails

numberColumn

public NumericColumn<?> numberColumn(String columnName)

doubleColumn

public DoubleColumn doubleColumn(String columnName)

doubleColumn

public DoubleColumn doubleColumn(int columnIndex)

stringColumns

public StringColumn[] stringColumns()

numberColumns

public NumericColumn<?>[] numberColumns()

numericColumns
```
public List<NumericColumn<?>> numericColumns()
```
Returns all the NumericColumns in the relation

numericColumns

public List<NumericColumn<?>> numericColumns(int... columnIndices)

Returns all the NumericColumns in the relation

numericColumns

public List<NumericColumn<?>> numericColumns(String... columnNames)

Returns all the NumericColumns in the relation

booleanColumns

public BooleanColumn[] booleanColumns()

dateColumns
```
public DateColumn[] dateColumns()
```

dateTimeColumns

public DateTimeColumn[] dateTimeColumns()

instantColumns

public InstantColumn[] instantColumns()

timeColumns
```
public TimeColumn[] timeColumns()
```

categoricalColumn

public CategoricalColumn<?> categoricalColumn(String columnName)

categoricalColumn

public CategoricalColumn<?> categoricalColumn(int columnNumber)

categoricalColumns

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

Returns the columns whose names are given in the input array

nCol
```
public NumericColumn<?> nCol(String columnName)
```
Returns the column with the given name cast to a NumberColumn
Shorthand for numberColumn()

nCol
```
public NumericColumn<?> nCol(int columnIndex)
```
Returns the column with the given name cast to a NumberColumn
Shorthand for numberColumn()

intColumn

public IntColumn intColumn(String columnName)

intColumn

public IntColumn intColumn(int columnIndex)

shortColumn

public ShortColumn shortColumn(String columnName)

shortColumn

public ShortColumn shortColumn(int columnIndex)

longColumn

public LongColumn longColumn(String columnName)

longColumn

public LongColumn longColumn(int columnIndex)

floatColumn

public FloatColumn floatColumn(String columnName)

floatColumn

public FloatColumn floatColumn(int columnIndex)

dateColumn

public DateColumn dateColumn(int columnIndex)

dateColumn

public DateColumn dateColumn(String columnName)

timeColumn

public TimeColumn timeColumn(String columnName)

timeColumn

public TimeColumn timeColumn(int columnIndex)

stringColumn

public StringColumn stringColumn(String columnName)

stringColumn

public StringColumn stringColumn(int columnIndex)

textColumn

public TextColumn textColumn(String columnName)

textColumn

public TextColumn textColumn(int columnIndex)

dateTimeColumn

public DateTimeColumn dateTimeColumn(int columnIndex)

dateTimeColumn

public DateTimeColumn dateTimeColumn(String columnName)

instantColumn

public InstantColumn instantColumn(int columnIndex)

instantColumn

public InstantColumn instantColumn(String columnName)

as
```
public TableConverter as()
```

smile
```
public SmileConverter smile()
```

getUnformatted
```
public String getUnformatted(int r,
                             int c)
```
Returns a string representation of the value at the given row and column indexes

Parameters:

r - the row index, 0 based

c - the column index, 0 based

getString
```
public String getString(int r,
                        String columnName)
```
Returns a string representation of the value at the given row and column indexes

Parameters:

r - the row index, 0 based

columnName - the name of the column to be returned
// TODO: performance would be enhanced if columns could be referenced via a hashTable

getString
```
public String getString(int r,
                        int columnIndex)
```
Returns a string representation of the value at the given row and column indexes

Parameters:

r - the row index, 0 based

columnIndex - the index of the column to be returned
// TODO: performance would be enhanced if columns could be referenced via a hashTable

containsColumn

public boolean containsColumn(Column<?> column)

containsColumn

public boolean containsColumn(String columnName)

Class Relation

Constructor Summary

Method Summary

Methods inherited from interface java.lang.Iterable

Methods inherited from class java.lang.Object

Constructor Detail

Relation

Method Detail

addColumns

setName

isEmpty

shape

removeColumns

removeColumns

removeColumns

columnsOfType

first

columnIndex

column

column

columnCount

rowCount

columns

columns

columns

columnIndex

get

name

clear

columnNames

columnTypes

typeArray

types

colWidths

toString

printAll

print

print

structure

summary

booleanColumn

booleanColumn

numberColumn

numberColumn

doubleColumn

doubleColumn

stringColumns

numberColumns

numericColumns

numericColumns

numericColumns

booleanColumns

dateColumns

dateTimeColumns

instantColumns

timeColumns

categoricalColumn

categoricalColumn

categoricalColumns

nCol

nCol

intColumn

intColumn

shortColumn

shortColumn

longColumn

longColumn

floatColumn

floatColumn

dateColumn

dateColumn

timeColumn

timeColumn

stringColumn

stringColumn

textColumn

textColumn

dateTimeColumn

dateTimeColumn

instantColumn