Package tech.tablesaw.table

Class 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 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

      • 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.

      • 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