Relation (tablesaw-core 0.43.1 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)`	Adds the given columns to this Relation and returns the same relation.
`TableConverter`	`as()`	Returns an `TableConverter` that can convert this Relation to a two-dimensional matrix of primitive numeric values
`BooleanColumn`	`booleanColumn(int columnIndex)`	Returns the DoubleColumn at the given 0-based index if present.
`BooleanColumn`	`booleanColumn(String columnName)`	Returns a BooleanColumn with the given name if it is present in this Relation.
`BooleanColumn[]`	`booleanColumns()`	Returns all BooleanColumns in this Relation as an Array
`CategoricalColumn<?>`	`categoricalColumn(int columnNumber)`	Returns the CategoricalColumn at the given 0-based index if present.
`CategoricalColumn<?>`	`categoricalColumn(String columnName)`	Returns a CategoricalColumn with the given name if it is present in this Relation.
`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()`	Returns a list containing the names of all the columns in this relation
`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)`	Returns a list containing all the columns of the given type in this Relation
`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)`	Returns true if a column with the given name is in this Relation
`boolean`	`containsColumn(Column<?> column)`	Returns true if the given column is in this Relation
`DateColumn`	`dateColumn(int columnIndex)`	Returns the DateColumn at the given 0-based index if present.
`DateColumn`	`dateColumn(String columnName)`	Returns a DateColumn with the given name if it is present in this Relation.
`DateColumn[]`	`dateColumns()`	Returns all DateColumns in this Relation as an Array
`DateTimeColumn`	`dateTimeColumn(int columnIndex)`	Returns the DateTimeColumn at the given 0-based index if present.
`DateTimeColumn`	`dateTimeColumn(String columnName)`	Returns a DateTimeColumn with the given name if it is present in this Relation.
`DateTimeColumn[]`	`dateTimeColumns()`	Returns all DateTimeColumns in this Relation as an Array
`DoubleColumn`	`doubleColumn(int columnIndex)`	Returns the DoubleColumn at the given 0-based index if present.
`DoubleColumn`	`doubleColumn(String columnName)`	Returns a DoubleColumn with the given name if it is present in this Relation.
`abstract Table`	`first(int nRows)`	Returns a new table containing the first n rows in this Relation
`FloatColumn`	`floatColumn(int columnIndex)`	Returns the FloatColumn at the given 0-based index if present.
`FloatColumn`	`floatColumn(String columnName)`	Returns a FloatColumn with the given name if it is present in this Relation.
`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)`	Returns the InstantColumn at the given 0-based index if present.
`InstantColumn`	`instantColumn(String columnName)`	Returns an InstantColumn with the given name if it is present in this Relation.
`InstantColumn[]`	`instantColumns()`	Returns all InstantColumns in this Relation as an Array
`IntColumn`	`intColumn(int columnIndex)`	Returns the IntColumn at the given 0-based index if present.
`IntColumn`	`intColumn(String columnName)`	Returns an IntColumn with the given name if it is present in this Relation.
`boolean`	`isEmpty()`	Returns true if this relation has zero rows and false otherwise.
`LongColumn`	`longColumn(int columnIndex)`	Returns the LongColumn at the given 0-based index if present.
`LongColumn`	`longColumn(String columnName)`	Returns a LongColumn with the given name if it is present in this Relation.
`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)`	Returns a NumericColumn with the given name if it is present in this Relation.
`NumericColumn<?>[]`	`numberColumns()`	Returns all the NumericColumns in this Relation as an Array
`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)`	Returns a 'pretty-printed' string representation of at most rowLimit rows from this relation.
`String`	`printAll()`	Returns a 'pretty-printed' string representation of this entire relation.
`Relation`	`removeColumns(int... columnIndexes)`	Removes the columns at the given 0-based indices from this Relation and returns the same relation.
`Relation`	`removeColumns(String... columnName)`	Removes the columns with the given namesfrom this Relation and returns the same relation.
`abstract Relation`	`removeColumns(Column<?>... columns)`	Removes the given columns from this Relation and returns the same relation.
`abstract int`	`rowCount()`	Returns the number of rows in the relation
`abstract Relation`	`setName(String name)`	Sets the name of this Relation and returns the same relation.
`String`	`shape()`	Returns a string that tells how many rows and columns this relation has
`ShortColumn`	`shortColumn(int columnIndex)`	Returns the ShortColumn at the given 0-based index if present.
`ShortColumn`	`shortColumn(String columnName)`	Returns a ShortColumn with the given name if it is present in this Relation.
`SmileConverter`	`smile()`	Returns an `SmileConverter` that can convert this table to a format suitable for use with the Smile machine learning library.
`StringColumn`	`stringColumn(int columnIndex)`	Returns the StringColumn at the given 0-based index if present.
`StringColumn`	`stringColumn(String columnName)`	Returns a StringColumn with the given name if it is present in this Relation.
`StringColumn[]`	`stringColumns()`	Returns all the StringColumns in this Relation as an Array
`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()`	Returns a table containing summary statistics for the columns in this Relation
`TextColumn`	`textColumn(int columnIndex)`	Returns the TextColumn at the given 0-based index if present.
`TextColumn`	`textColumn(String columnName)`	Returns a TextColumn with the given name if it is present in this Relation.
`TimeColumn`	`timeColumn(int columnIndex)`	Returns the TimeColumn at the given 0-based index if present.
`TimeColumn`	`timeColumn(String columnName)`	Returns a TimeColumn with the given name if it is present in this Relation.
`TimeColumn[]`	`timeColumns()`	Returns all TimeColumns in this Relation as an Array
`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)
```
    Adds the given columns to this Relation and returns the same relation.
    
    Returns:
    
    This Relation
  - setName
```
public abstract Relation setName(String name)
```
    Sets the name of this Relation and returns the same relation.
    
    Returns:
    
    This Relation
  - isEmpty
```
public boolean isEmpty()
```
    Returns true if this relation has zero rows and false otherwise. Rows of missing values are counted.
  - shape
```
public String shape()
```
    Returns a string that tells how many rows and columns this relation has
  - removeColumns
```
public Relation removeColumns(int... columnIndexes)
```
    Removes the columns at the given 0-based indices from this Relation and returns the same relation.
    
    Returns:
    
    This Relation
  - removeColumns
```
public abstract Relation removeColumns(Column<?>... columns)
```
    Removes the given columns from this Relation and returns the same relation.
    
    Returns:
    
    This Relation
  - removeColumns
```
public Relation removeColumns(String... columnName)
```
    Removes the columns with the given namesfrom this Relation and returns the same relation.
    
    Returns:
    
    This Relation
  - columnsOfType
```
public List<Column<?>> columnsOfType(ColumnType type)
```
    Returns a list containing all the columns of the given type in this Relation
  - first
```
public abstract Table first(int nRows)
```
    Returns a new table containing the first n rows in this Relation
  - 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()
```
    Returns a list containing the names of all the columns in this relation
  - 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()
```
    Returns a 'pretty-printed' string representation of this entire relation.
  - print
```
public String print(int rowLimit)
```
    Returns a 'pretty-printed' string representation of at most rowLimit rows from this relation.
  - 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()
```
    Returns a table containing summary statistics for the columns in this Relation
  - booleanColumn
```
public BooleanColumn booleanColumn(int columnIndex)
```
    Returns the DoubleColumn at the given 0-based index if present. A ClassCastException is the column is of a different type.
  - booleanColumn
```
public BooleanColumn booleanColumn(String columnName)
```
    Returns a BooleanColumn with the given name if it is present in this Relation. If the column is of a different type, a ClassCastException is thrown
  - 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)
```
    Returns a NumericColumn with the given name if it is present in this Relation. If the column is not Numeric, a ClassCastException is thrown
  - doubleColumn
```
public DoubleColumn doubleColumn(String columnName)
```
    Returns a DoubleColumn with the given name if it is present in this Relation. If the column is not of type DOUBLE, a ClassCastException is thrown
  - doubleColumn
```
public DoubleColumn doubleColumn(int columnIndex)
```
    Returns the DoubleColumn at the given 0-based index if present. A ClassCastException is the column is of a different type.
  - stringColumns
```
public StringColumn[] stringColumns()
```
    Returns all the StringColumns in this Relation as an Array
  - numberColumns
```
public NumericColumn<?>[] numberColumns()
```
    Returns all the NumericColumns in this Relation as an Array
  - 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()
```
    Returns all BooleanColumns in this Relation as an Array
  - dateColumns
```
public DateColumn[] dateColumns()
```
    Returns all DateColumns in this Relation as an Array
  - dateTimeColumns
```
public DateTimeColumn[] dateTimeColumns()
```
    Returns all DateTimeColumns in this Relation as an Array
  - instantColumns
```
public InstantColumn[] instantColumns()
```
    Returns all InstantColumns in this Relation as an Array
  - timeColumns
```
public TimeColumn[] timeColumns()
```
    Returns all TimeColumns in this Relation as an Array
  - categoricalColumn
```
public CategoricalColumn<?> categoricalColumn(String columnName)
```
    Returns a CategoricalColumn with the given name if it is present in this Relation. If the column is not Categorical, a ClassCastException is thrown
  - categoricalColumn
```
public CategoricalColumn<?> categoricalColumn(int columnNumber)
```
    Returns the CategoricalColumn at the given 0-based index if present. A ClassCastException is thrown otherwise
  - 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. If the column is not Numeric, a ClassCastException is thrown
    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)
```
    Returns an IntColumn with the given name if it is present in this Relation. If the column has a different type, a ClassCastException is thrown.
  - intColumn
```
public IntColumn intColumn(int columnIndex)
```
    Returns the IntColumn at the given 0-based index if present. A ClassCastException is the column is of a different type.
  - shortColumn
```
public ShortColumn shortColumn(String columnName)
```
    Returns a ShortColumn with the given name if it is present in this Relation. If the column has a different type, a ClassCastException is thrown.
  - shortColumn
```
public ShortColumn shortColumn(int columnIndex)
```
    Returns the ShortColumn at the given 0-based index if present. A ClassCastException is the column is of a different type.
  - longColumn
```
public LongColumn longColumn(String columnName)
```
    Returns a LongColumn with the given name if it is present in this Relation. If the column has a different type, a ClassCastException is thrown.
  - longColumn
```
public LongColumn longColumn(int columnIndex)
```
    Returns the LongColumn at the given 0-based index if present. A ClassCastException is the column is of a different type.
  - floatColumn
```
public FloatColumn floatColumn(String columnName)
```
    Returns a FloatColumn with the given name if it is present in this Relation. If the column has a different type, a ClassCastException is thrown.
  - floatColumn
```
public FloatColumn floatColumn(int columnIndex)
```
    Returns the FloatColumn at the given 0-based index if present. A ClassCastException is the column is of a different type.
  - dateColumn
```
public DateColumn dateColumn(int columnIndex)
```
    Returns the DateColumn at the given 0-based index if present. A ClassCastException is the column is of a different type.
  - dateColumn
```
public DateColumn dateColumn(String columnName)
```
    Returns a DateColumn with the given name if it is present in this Relation. If the column has a different type, a ClassCastException is thrown.
  - timeColumn
```
public TimeColumn timeColumn(String columnName)
```
    Returns a TimeColumn with the given name if it is present in this Relation. If the column has a different type, a ClassCastException is thrown.
  - timeColumn
```
public TimeColumn timeColumn(int columnIndex)
```
    Returns the TimeColumn at the given 0-based index if present. A ClassCastException is the column is of a different type.
  - stringColumn
```
public StringColumn stringColumn(String columnName)
```
    Returns a StringColumn with the given name if it is present in this Relation. If the column has a different type, a ClassCastException is thrown.
  - stringColumn
```
public StringColumn stringColumn(int columnIndex)
```
    Returns the StringColumn at the given 0-based index if present. A ClassCastException is the column is of a different type.
  - textColumn
```
public TextColumn textColumn(String columnName)
```
    Returns a TextColumn with the given name if it is present in this Relation. If the column has a different type, a ClassCastException is thrown.
  - textColumn
```
public TextColumn textColumn(int columnIndex)
```
    Returns the TextColumn at the given 0-based index if present. A ClassCastException is the column is of a different type.
  - dateTimeColumn
```
public DateTimeColumn dateTimeColumn(int columnIndex)
```
    Returns the DateTimeColumn at the given 0-based index if present. A ClassCastException is the column is of a different type.
  - dateTimeColumn
```
public DateTimeColumn dateTimeColumn(String columnName)
```
    Returns a DateTimeColumn with the given name if it is present in this Relation. If the column has a different type, a ClassCastException is thrown.
  - instantColumn
```
public InstantColumn instantColumn(int columnIndex)
```
    Returns the InstantColumn at the given 0-based index if present. A ClassCastException is the column is of a different type.
  - instantColumn
```
public InstantColumn instantColumn(String columnName)
```
    Returns an InstantColumn with the given name if it is present in this Relation. If the column has a different type, a ClassCastException is thrown.
  - as
```
public TableConverter as()
```
    Returns an TableConverter that can convert this Relation to a two-dimensional matrix of primitive numeric values
  - smile
```
public SmileConverter smile()
```
    Returns an SmileConverter that can convert this table to a format suitable for use with the Smile machine learning library.
  - 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)
```
    Returns true if the given column is in this Relation
  - containsColumn
```
public boolean containsColumn(String columnName)
```
    Returns true if a column with the given name is in this Relation

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