Package tech.tablesaw.columns

Interface Column<T>

All Superinterfaces:
Comparator<T>, Iterable<T>
All Known Subinterfaces:
BooleanMapUtils, CategoricalColumn<T>, DateFilters, DateMapFunctions, DateTimeFilters, DateTimeMapFunctions, NumericColumn<T>, StringFilters, StringMapFunctions, StringReduceUtils, TemporalColumn<T>, TemporalFilters<T>, TemporalMapFunctions<C,T>, TimeFilters, TimeMapFunctions
All Known Implementing Classes:
AbstractColumn, AbstractStringColumn, BooleanColumn, DateColumn, DateTimeColumn, DoubleColumn, FloatColumn, InstantColumn, IntColumn, LongColumn, NumberColumn, ShortColumn, StringColumn, TextColumn, TimeColumn
public interface Column<T> extends Iterable<T>, Comparator<T>
The general interface for columns.

Columns can either exist on their own or be a part of a table. All the data in a single column is of a particular type.

  • Method Summary

    Modifier and Type
    Method
    Description
    default boolean
    allMatch(Predicate<? super T> test)
    Returns true if all rows satisfy the predicate, false otherwise
    default boolean
    anyMatch(Predicate<? super T> test)
    Returns true if any row satisfies the predicate, false otherwise
    Column<T>
    append(T value)
    Appends value to the bottom of this column and return this column
    Column<T>
    append(Column<T> column)
    Appends all the values in the argument to the bottom of this column and return this column
    Column<T>
    append(Column<T> column, int row)
    Appends the value at the given row in the given column to the bottom of this column and return this column
    Column<T>
    appendCell(String stringValue)
    Add one element to the bottom of this column and set its value to the parsed value of the given String.
    Column<T>
    appendCell(String stringValue, AbstractColumnParser<?> parser)
    Add one element to the bottom of this column and set its value to the parsed value of the given String, as performed by the given parser
    Column<T>
    appendMissing()
    Appends a missing value appropriate to the column
    Column<T>
    appendObj(Object value)
    Appends the given value to the bottom of this column and return this column
    byte[]
    asBytes(int rowNumber)
    Returns the contents of the cell at rowNumber as a byte[].
    default List<T>
    asList()
    Returns a list of all the elements in this column
    T[]
    asObjectArray()
    Returns an array of objects as appropriate for my type of column
    Set<T>
    asSet()
    Returns a Set containing all the unique values in this column
    StringColumn
    asStringColumn()
    Returns a StringColumn consisting of the (unformatted) String representation of this column values
    int
    byteSize()
    Returns the width of a cell in this column, in bytes.
    void
    clear()
    Removes all elements TODO: Make this return this column
    default int
    columnWidth()
    Returns the width of the column in characters, for printing
    default boolean
    contains(T object)
    Returns true if the given object appears in this column, and false otherwise
    Column<T>
    copy()
    Returns a deep copy of the receiver
    default int
    count(Predicate<? super T> test)
    Counts the number of rows satisfying predicate
    default int
    count(Predicate<? super T> test, int max)
    Counts the number of rows satisfying predicate, but only upto the max value
    int
    countMissing()
    Returns the count of missing values in this column.
    default int
    countUnique()
    Returns the count of unique values in this column.
    Column<T>
    emptyCopy()
    Returns a copy of the receiver with no data.
    Column<T>
    emptyCopy(int rowSize)
    Returns an empty copy of the receiver, with its internal storage initialized to the given row size.
    boolean
    equals(int rowNumber1, int rowNumber2)
    Returns true if the value in this column at rowNumber1 is equal to the value at rowNumber2
    default Column<T>
    filter(Predicate<? super T> test)
    Returns a new Column of the same type with only those rows satisfying the predicate
    default Column<T>
    first(int numRows)
    Returns a column of the same type containing the first numRows of this column.
    T
    get(int row)
    Returns the value at the given zero-based index
    String
    getString(int row)
    Returns a string representation of the value at the given row.
    String
    getUnformattedString(int r)
    Returns a String representation of the value at index r, without any formatting applied
    int
    indexOf(Object o)
    Returns the index of the first occurrence of o in the column or -1 if the element is not in the column.
    default Column<T>
    inRange(int start, int end)
    Returns a column containing the rows in this column beginning with start inclusive, and ending with end exclusive
    default Interpolator<T>
    interpolate()
    Provides the ability to create a new column with missing cells filled based off the value of nearby cells.
    boolean
    isEmpty()
    Returns true if the column has no data
    Selection
    isMissing()
    Returns a selection containing an index for every missing value in this column
    boolean
    isMissing(int rowNumber)
    Returns true if the value at rowNumber is missing
    Selection
    isNotMissing()
    Returns a selection containing an index for every non-missing value in this column
    Column<T>
    lag(int n)
    Returns a column of the same type and size as the receiver, containing the receivers values offset by n.
    default Column<T>
    last(int numRows)
    Returns a column of the same type containing the last numRows of this column.
    default Column<T>
    lead(int n)
    Returns a column of the same type as the receiver, containing the receivers values offset -n For example if you lead a column containing 2, 3, 4 by 1, you get a column containing 3, 4, NA.
    default <R, C extends Column<R>>
    C
    map(Function<? super T,? extends R> fun, Function<String,C> creator)
    Maps the function across all rows, appending the results to the created Column.
    default Column<T>
    map(Function<? super T,? extends T> fun)
    Maps the function across all rows, appending the results to a new Column of the same type
    default <R, C extends Column<R>>
    C
    mapInto(Function<? super T,? extends R> fun, C into)
    Maps the function across all rows, storing the results into the provided Column.
    default Optional<T>
    max(Comparator<? super T> comp)
    Returns the maximum row according to the provided Comparator
    default Column<T>
    max(Column<T> other)
    Returns a column containing the element-wise min between this column and other column
    default Optional<T>
    min(Comparator<? super T> comp)
    Returns the minimum value according to the provided Comparator
    default Column<T>
    min(Column<T> other)
    Returns a column containing the element-wise min between this column and other column
    String
    name()
    Returns the column's name.
    default boolean
    noneMatch(Predicate<? super T> test)
    Returns true if no row satisfies the predicate, false otherwise
    AbstractColumnParser<T>
    parser()
    Returns the parser used by appendCell(String) ()}.
    default String
    print()
    TODO(lwhite): Print n from the top and bottom, like a table;
    default Optional<T>
    reduce(BinaryOperator<T> op)
    Reduction with binary operator
    default T
    reduce(T initial, BinaryOperator<T> op)
    Reduction with binary operator and initial value
    Column<T>
    removeMissing()
    Returns a copy of this column with the missing values removed
    default RollingColumn
    rolling(int windowSize)
    Returns a RollingColumn with the given windowSize, which can be used for performing calculations on rolling subsets of my data
    it.unimi.dsi.fastutil.ints.IntComparator
    rowComparator()
    Returns an IntComparator for sorting my rows
    default Column<T>
    sampleN(int n)
    Returns a column containing a random sample of the values in this column
    default Column<T>
    sampleX(double proportion)
    Returns a table consisting of randomly selected values from this column.
    default Column<T>
    set(int row, String stringValue, AbstractColumnParser<?> parser)
    Sets the value at row to the parsed value of the given String using the given parser and returns this column
    Column<T>
    set(int row, T value)
    Sets the value at index row to the given value and return this column
    Column<T>
    set(int row, Column<T> sourceColumn, int sourceRow)
    Sets the value at row to the value at sourceRow in the given column and return this column
    default Column<T>
    set(Predicate<T> condition, Column<T> other)
    Updates this column where values matching the selection are replaced with the corresponding value from the given column
    default Column<T>
    set(Selection rowSelection, T newValue)
    Conditionally update this column, replacing current values with newValue for all rows where the current value matches the selection criteria
    default Column<T>
    set(Selection condition, Column<T> other)
    Updates this column where values matching the selection are replaced with the corresponding value from the given column
    Column<T>
    setMissing(int i)
    Sets the value at index i to the missing-value indicator for this column type, and return this column
    default Column<T>
    setMissingTo(T newValue)
    Sets the value of any missing data in the column to newValue and returns the same column
    Column<T>
    setName(String name)
    Sets the columns name to the given string
    Column<T>
    setParser(AbstractColumnParser<T> parser)
    Sets the parser used by appendCell(String)
    int
    size()
    Returns the number of elements in this column, including missing values
    void
    sortAscending()
    Sorts my values in ascending order
    void
    sortDescending()
    Sorts my values in descending order
    default Column<T>
    sorted(Comparator<? super T> comp)
    Returns a new Column of the same type sorted according to the provided Comparator
    default Column<T>
    subset(int[] rows)
    Return a column of the same type containing just those elements whose indexes are included in the given array
    Table
    summary()
    Returns a table containing a ColumnType specific summary of the data in this column
    default String
    title()
     
    ColumnType
    type()
    Returns this column's ColumnType
    Column<T>
    unique()
    Returns a column of the same type containing only the unique values
    int
    valueHash(int rowNumber)
    Returns an int suitable as a hash for the value in this column at the given index
    Column<T>
    where(Selection selection)
    Returns a new column containing the subset referenced by the Selection

    Methods inherited from interface java.util.Comparator

    compare, equals, reversed, thenComparing, thenComparing, thenComparing, thenComparingDouble, thenComparingInt, thenComparingLong

    Methods inherited from interface java.lang.Iterable

    forEach, iterator, spliterator

  • Method Details

    • size

      int size()
      Returns the number of elements in this column, including missing values

    • summary

      Table summary()
      Returns a table containing a ColumnType specific summary of the data in this column

    • asObjectArray

      T[] asObjectArray()
      Returns an array of objects as appropriate for my type of column

    • countMissing

      int countMissing()
      Returns the count of missing values in this column.
      Returns:
      missing values as int

    • countUnique

      default int countUnique()
      Returns the count of unique values in this column.
      Returns:
      unique values as int

    • name

      String name()
      Returns the column's name.
      Returns:
      name as String

    • type

      ColumnType type()
      Returns this column's ColumnType
      Returns:
      ColumnType

    • parser

      AbstractColumnParser<T> parser()
      Returns the parser used by appendCell(String) ()}.
      Returns:
      AbstractColumnParser

    • getString

      String getString(int row)
      Returns a string representation of the value at the given row.
      Parameters:
      row - The index of the row.
      Returns:
      value as String

    • get

      T get(int row)
      Returns the value at the given zero-based index

    • reduce

      default T reduce(T initial, BinaryOperator<T> op)
      Reduction with binary operator and initial value
      Parameters:
      initial - initial value
      op - the operator
      Returns:
      the result of reducing initial value and all rows with operator

    • reduce

      default Optional<T> reduce(BinaryOperator<T> op)
      Reduction with binary operator
      Parameters:
      op - the operator
      Returns:
      Optional with the result of reducing all rows with operator

    • clear

      void clear()
      Removes all elements TODO: Make this return this column

    • sortAscending

      void sortAscending()
      Sorts my values in ascending order

    • sortDescending

      void sortDescending()
      Sorts my values in descending order

    • isEmpty

      boolean isEmpty()
      Returns true if the column has no data
      Returns:
      true if empty, false if not

    • rowComparator

      it.unimi.dsi.fastutil.ints.IntComparator rowComparator()
      Returns an IntComparator for sorting my rows

    • title

      default String title()

    • isMissing

      Selection isMissing()
      Returns a selection containing an index for every missing value in this column

    • isNotMissing

      Selection isNotMissing()
      Returns a selection containing an index for every non-missing value in this column

    • byteSize

      int byteSize()
      Returns the width of a cell in this column, in bytes.
      Returns:
      width in bytes

    • asBytes

      byte[] asBytes(int rowNumber)
      Returns the contents of the cell at rowNumber as a byte[].
      Parameters:
      rowNumber - index of the row
      Returns:
      content as byte[]

    • asSet

      Set<T> asSet()
      Returns a Set containing all the unique values in this column

    • rolling

      default RollingColumn rolling(int windowSize)
      Returns a RollingColumn with the given windowSize, which can be used for performing calculations on rolling subsets of my data
      Parameters:
      windowSize - The number of elements to include in each calculation
      Returns:
      a RollingColumn

    • getUnformattedString

      String getUnformattedString(int r)
      Returns a String representation of the value at index r, without any formatting applied

    • isMissing

      boolean isMissing(int rowNumber)
      Returns true if the value at rowNumber is missing

    • print

      default String print()
      TODO(lwhite): Print n from the top and bottom, like a table;

    • columnWidth

      default int columnWidth()
      Returns the width of the column in characters, for printing

    • asList

      default List<T> asList()
      Returns a list of all the elements in this column

      Note, if a value in the column is missing, a null is added in it's place

    • contains

      default boolean contains(T object)
      Returns true if the given object appears in this column, and false otherwise

      TODO override in column subtypes for performance

    • count

      default int count(Predicate<? super T> test, int max)
      Counts the number of rows satisfying predicate, but only upto the max value
      Parameters:
      test - the predicate
      max - the maximum number of rows to count
      Returns:
      the number of rows satisfying the predicate

    • count

      default int count(Predicate<? super T> test)
      Counts the number of rows satisfying predicate
      Parameters:
      test - the predicate
      Returns:
      the number of rows satisfying the predicate

    • allMatch

      default boolean allMatch(Predicate<? super T> test)
      Returns true if all rows satisfy the predicate, false otherwise
      Parameters:
      test - the predicate
      Returns:
      true if all rows satisfy the predicate, false otherwise

    • anyMatch

      default boolean anyMatch(Predicate<? super T> test)
      Returns true if any row satisfies the predicate, false otherwise
      Parameters:
      test - the predicate
      Returns:
      true if any rows satisfies the predicate, false otherwise

    • noneMatch

      default boolean noneMatch(Predicate<? super T> test)
      Returns true if no row satisfies the predicate, false otherwise
      Parameters:
      test - the predicate
      Returns:
      true if no row satisfies the predicate, false otherwise

    • max

      default Optional<T> max(Comparator<? super T> comp)
      Returns the maximum row according to the provided Comparator
      Parameters:
      comp -
      Returns:
      the maximum row

    • min

      default Optional<T> min(Comparator<? super T> comp)
      Returns the minimum value according to the provided Comparator
      Parameters:
      comp - the Comparator to use
      Returns:
      the minimum value

    • mapInto

      default <R, C extends Column<R>> C mapInto(Function<? super T,? extends R> fun, C into)
      Maps the function across all rows, storing the results into the provided Column.

      The target column must have at least the same number of rows.

      Parameters:
      fun - function to map
      into - Column into which results are set
      Returns:
      the provided Column

    • map

      default <R, C extends Column<R>> C map(Function<? super T,? extends R> fun, Function<String,C> creator)
      Maps the function across all rows, appending the results to the created Column.

      Example: 

       DoubleColumn d;
 StringColumn s = d.map(String::valueOf, StringColumn::create);
      Parameters:
      fun - function to map
      creator - the creator of the Column. Its String argument will be the name of the current column (see name())
      Returns:
      the Column with the results

    • setMissing

      Column<T> setMissing(int i)
      Sets the value at index i to the missing-value indicator for this column type, and return this column

    • setMissingTo

      default Column<T> setMissingTo(T newValue)
      Sets the value of any missing data in the column to newValue and returns the same column
      Parameters:
      newValue - the value to be used for all missing data in this column
      Returns:
      the column updated

    • filter

      default Column<T> filter(Predicate<? super T> test)
      Returns a new Column of the same type with only those rows satisfying the predicate
      Parameters:
      test - the predicate
      Returns:
      a new Column of the same type with only those rows satisfying the predicate

    • subset

      default Column<T> subset(int[] rows)
      Return a column of the same type containing just those elements whose indexes are included in the given array

    • sorted

      default Column<T> sorted(Comparator<? super T> comp)
      Returns a new Column of the same type sorted according to the provided Comparator
      Parameters:
      comp - the Comparator
      Returns:
      a sorted Column

    • emptyCopy

      Column<T> emptyCopy()
      Returns a copy of the receiver with no data. The column name and type are the same.
      Returns:
      a empty copy of Column

    • copy

      Column<T> copy()
      Returns a deep copy of the receiver
      Returns:
      a Column

    • emptyCopy

      Column<T> emptyCopy(int rowSize)
      Returns an empty copy of the receiver, with its internal storage initialized to the given row size.
      Parameters:
      rowSize - the initial row size
      Returns:
      a Column

    • map

      default Column<T> map(Function<? super T,? extends T> fun)
      Maps the function across all rows, appending the results to a new Column of the same type
      Parameters:
      fun - function to map
      Returns:
      the Column with the results

    • min

      default Column<T> min(Column<T> other)
      Returns a column containing the element-wise min between this column and other column

      TODO(lwhite) Override in column subtypes for better performance

    • max

      default Column<T> max(Column<T> other)
      Returns a column containing the element-wise min between this column and other column

      TODO(lwhite) Override in column subtypes for better performance

    • set

      default Column<T> set(Predicate<T> condition, Column<T> other)
      Updates this column where values matching the selection are replaced with the corresponding value from the given column

    • set

      default Column<T> set(Selection condition, Column<T> other)
      Updates this column where values matching the selection are replaced with the corresponding value from the given column

    • lead

      default Column<T> lead(int n)
      Returns a column of the same type as the receiver, containing the receivers values offset -n For example if you lead a column containing 2, 3, 4 by 1, you get a column containing 3, 4, NA.

    • set

      default Column<T> set(Selection rowSelection, T newValue)
      Conditionally update this column, replacing current values with newValue for all rows where the current value matches the selection criteria

    • lag

      Column<T> lag(int n)
      Returns a column of the same type and size as the receiver, containing the receivers values offset by n.

      For example if you lag a column containing 2, 3, 4 by 1, you get a column containing NA, 2, 3

    • appendCell

      Column<T> appendCell(String stringValue)
      Add one element to the bottom of this column and set its value to the parsed value of the given String. Parsing is type-specific

    • appendCell

      Column<T> appendCell(String stringValue, AbstractColumnParser<?> parser)
      Add one element to the bottom of this column and set its value to the parsed value of the given String, as performed by the given parser

    • set

      Column<T> set(int row, T value)
      Sets the value at index row to the given value and return this column

    • set

      default Column<T> set(int row, String stringValue, AbstractColumnParser<?> parser)
      Sets the value at row to the parsed value of the given String using the given parser and returns this column

    • set

      Column<T> set(int row, Column<T> sourceColumn, int sourceRow)
      Sets the value at row to the value at sourceRow in the given column and return this column

    • append

      Column<T> append(T value)
      Appends value to the bottom of this column and return this column

    • append

      Column<T> append(Column<T> column)
      Appends all the values in the argument to the bottom of this column and return this column

    • append

      Column<T> append(Column<T> column, int row)
      Appends the value at the given row in the given column to the bottom of this column and return this column

    • appendObj

      Column<T> appendObj(Object value)
      Appends the given value to the bottom of this column and return this column

    • appendMissing

      Column<T> appendMissing()
      Appends a missing value appropriate to the column

    • valueHash

      int valueHash(int rowNumber)
      Returns an int suitable as a hash for the value in this column at the given index

    • equals

      boolean equals(int rowNumber1, int rowNumber2)
      Returns true if the value in this column at rowNumber1 is equal to the value at rowNumber2

    • where

      Column<T> where(Selection selection)
      Returns a new column containing the subset referenced by the Selection

    • removeMissing

      Column<T> removeMissing()
      Returns a copy of this column with the missing values removed

    • unique

      Column<T> unique()
      Returns a column of the same type containing only the unique values
      Returns:
      a Column

    • first

      default Column<T> first(int numRows)
      Returns a column of the same type containing the first numRows of this column.

    • last

      default Column<T> last(int numRows)
      Returns a column of the same type containing the last numRows of this column.

    • setName

      Column<T> setName(String name)
      Sets the columns name to the given string
      Parameters:
      name - The new name MUST be unique for any table containing this column
      Returns:
      this Column to allow method chaining

    • setParser

      Column<T> setParser(AbstractColumnParser<T> parser)
      Sets the parser used by appendCell(String)
      Parameters:
      parser - a column parser that converts text input to the column data type
      Returns:
      this Column to allow method chaining

    • inRange

      default Column<T> inRange(int start, int end)
      Returns a column containing the rows in this column beginning with start inclusive, and ending with end exclusive

    • sampleN

      default Column<T> sampleN(int n)
      Returns a column containing a random sample of the values in this column
      Parameters:
      n - the number of values to select
      Returns:
      A column of the same type as the receiver

    • sampleX

      default Column<T> sampleX(double proportion)
      Returns a table consisting of randomly selected values from this column. The sample size is based on the given proportion of the total number of cells in this column
      Parameters:
      proportion - The proportion to go in the sample

    • interpolate

      default Interpolator<T> interpolate()
      Provides the ability to create a new column with missing cells filled based off the value of nearby cells.

    • asStringColumn

      StringColumn asStringColumn()
      Returns a StringColumn consisting of the (unformatted) String representation of this column values
      Returns:
      a StringColumn built using the column getUnformattedString(int) method

    • indexOf

      int indexOf(Object o)
      Returns the index of the first occurrence of o in the column or -1 if the element is not in the column.