tech.tablesaw.api

Class StringColumn

java.lang.Object

tech.tablesaw.columns.AbstractColumn<C,String>

tech.tablesaw.columns.strings.AbstractStringColumn<StringColumn>

tech.tablesaw.api.StringColumn

All Implemented Interfaces:

Iterable<String>, Comparator<String>, CategoricalColumn<String>, Column<String>, StringFilters, StringMapFunctions, StringReduceUtils, FilterSpec<Selection>, StringFilterSpec<Selection>

public class StringColumn
extends AbstractStringColumn<StringColumn>

A column that contains String values. They are assumed to be 'categorical' rather than free-form text, so are stored in an encoding that takes advantage of the expected repetition of string values.

Because the MISSING_VALUE for this column type is an empty string, there is little or no need for special handling of missing values in this class's methods.

Field Summary

Fields inherited from class tech.tablesaw.columns.AbstractColumn

DEFAULT_ARRAY_SIZE

Method Summary

Modifier and Type	Method and Description
StringColumn	addAll(List<String> stringValues) Add all the strings in the list to this column
StringColumn	append(Column<String> column)
StringColumn	append(String value) Added for naming consistency with all other columns
StringColumn	appendCell(String object)
StringColumn	appendCell(String object, AbstractColumnParser<?> parser)
StringColumn	appendMissing() Appends a missing value appropriate to the column
StringColumn	appendObj(Object obj)
byte[]	asBytes(int rowNumber) Returns the contents of the cell at rowNumber as a byte[]
double[]	asDoubleArray()
DoubleColumn	asDoubleColumn()
List<String>	asList() Returns a List<String> representation of all the values in this column
String[]	asObjectArray()
Set<String>	asSet()
StringColumn	asStringColumn() Returns a StringColumn consisting of the (unformatted) String representation of this column values
TextColumn	asTextColumn()
void	clear()
boolean	contains(String aString) Returns true if this column contains a cell with the given string, and false otherwise
StringColumn	copy() Returns a deep copy of the receiver
Table	countByCategory()
int	countMissing() Returns the count of missing values in this column
int	countOccurrences(String value)
int	countUnique() Returns the count of unique values in this column.
static StringColumn	create(String name)
static StringColumn	create(String name, int size)
static StringColumn	create(String name, List<String> strings)
static StringColumn	create(String name, Stream<String> stream)
static StringColumn	create(String name, String[] strings)
static StringColumn	createInternal(String name, DictionaryMap map)
StringColumn	emptyCopy() Returns a copy of the receiver with no data.
StringColumn	emptyCopy(int rowSize) Returns an empty copy of the receiver, with its internal storage initialized to the given row size.
int	firstIndexOf(String value)
String	get(int rowIndex) Returns the value at rowIndex in this column.
double	getDouble(int i)
List<BooleanColumn>	getDummies() Returns a list of boolean columns suitable for use as dummy variables in, for example, regression analysis, select a column of categorical data must be encoded as a list of columns, such that each column represents a single category and indicates whether it is present (1) or not present (0)
LookupTableWrapper	getLookupTable() For tablesaw internal use only
boolean	isEmpty() Returns true if the column has no data
Selection	isEqualTo(String string)
Selection	isIn(Collection<String> strings)
Selection	isIn(String... strings)
boolean	isMissing(int rowNumber)
Selection	isNotEqualTo(String string)
Selection	isNotIn(Collection<String> strings)
Selection	isNotIn(String... strings)
Iterator<String>	iterator()
StringColumn	lag(int n) Returns a column of the same type and size as the receiver, containing the receivers values offset by n.
StringColumn	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.
StringColumn	removeMissing()
it.unimi.dsi.fastutil.ints.IntComparator	rowComparator()
StringColumn	set(int rowIndex, String stringValue)
StringColumn	set(Selection rowSelection, String newValue) Conditionally update this column, replacing current values with newValue for all rows where the current value matches the selection criteria
Column<String>	setMissing(int i)
int	size() Returns the number of elements (a.k.a.
void	sortAscending()
void	sortDescending()
Table	summary()
StringColumn	unique() Returns a new Column containing all the unique values in this column
static boolean	valueIsMissing(String string)
StringColumn	where(Selection selection)

Methods inherited from class tech.tablesaw.columns.strings.AbstractStringColumn

append, bottom, byteSize, compare, getPrintFormatter, getString, getUnformattedString, set, setPrintFormatter, top

Methods inherited from class tech.tablesaw.columns.AbstractColumn

filter, first, inRange, last, map, max, min, name, sampleN, sampleX, set, setName, sorted, subset, toString, type

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface tech.tablesaw.columns.strings.StringFilters

containsString, endsWith, equalsIgnoreCase, equalsIgnoreCase, eval, eval, eval, eval, isAlpha, isAlphaNumeric, isEmptyString, isEqualTo, isLongerThan, isLowerCase, isMissing, isNotEqualTo, isNotMissing, isNumeric, isShorterThan, isUpperCase, lengthEquals, matchesRegex, startsWith, startsWith

Methods inherited from interface tech.tablesaw.columns.strings.StringMapFunctions

abbreviate, capitalize, commonPrefix, commonSuffix, concatenate, concatenate, countTokens, distance, format, join, length, lowerCase, padEnd, padStart, parseDouble, parseFloat, parseInt, repeat, replaceAll, replaceAll, replaceFirst, substring, substring, tokenizeAndRemoveDuplicates, tokenizeAndSort, tokenizeAndSort, tokens, trim, uniqueTokens, upperCase

Methods inherited from interface tech.tablesaw.columns.strings.StringReduceUtils

appendAll, appendAll

Methods inherited from interface tech.tablesaw.columns.Column

allMatch, anyMatch, columnWidth, count, count, filter, first, inRange, interpolate, last, map, map, mapInto, max, max, min, min, name, noneMatch, print, reduce, reduce, rolling, sampleN, sampleX, set, set, setMissingTo, setName, sorted, subset, title, type

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Methods inherited from interface java.util.Comparator

comparing, comparing, comparingDouble, comparingInt, comparingLong, equals, naturalOrder, nullsFirst, nullsLast, reversed, reverseOrder, thenComparing, thenComparing, thenComparing, thenComparingDouble, thenComparingInt, thenComparingLong

Method Detail

valueIsMissing

public static boolean valueIsMissing(String string)

appendMissing

public StringColumn appendMissing()

Description copied from interface: Column

Appends a missing value appropriate to the column

create

public static StringColumn create(String name)

create

public static StringColumn create(String name,
                                  String[] strings)

create

public static StringColumn create(String name,
                                  List<String> strings)

createInternal

public static StringColumn createInternal(String name,
                                          DictionaryMap map)

create

public static StringColumn create(String name,
                                  int size)

create

public static StringColumn create(String name,
                                  Stream<String> stream)

isMissing

public boolean isMissing(int rowNumber)

emptyCopy

public StringColumn emptyCopy()

Description copied from interface: Column

Returns a copy of the receiver with no data. The column name and type are the same.

Specified by:

emptyCopy in interface Column<String>

Specified by:

emptyCopy in class AbstractColumn<StringColumn,String>

Returns:

a empty copy of Column

emptyCopy

public StringColumn emptyCopy(int rowSize)

Description copied from interface: Column

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

sortAscending

public void sortAscending()

sortDescending

public void sortDescending()

size

public int size()

Returns the number of elements (a.k.a. rows or cells) in the column

Returns:

size as int

get

public String get(int rowIndex)

Returns the value at rowIndex in this column. The index is zero-based.

Parameters:

rowIndex - index of the row

Returns:

value as String

Throws:

IndexOutOfBoundsException - if the given rowIndex is not in the column

asList

public List<String> asList()

Returns a List<String> representation of all the values in this column

NOTE: Unless you really need a string consider using the column itself for large datasets as it uses much less memory

Returns:

values as a list of String.

summary

public Table summary()

countByCategory

public Table countByCategory()

clear

public void clear()

lead

public StringColumn lead(int n)

Description copied from interface: Column

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.

lag

public StringColumn lag(int n)

Description copied from interface: Column

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

set

public StringColumn set(Selection rowSelection,
                        String newValue)

Conditionally update this column, replacing current values with newValue for all rows where the current value matches the selection criteria

Examples: myCatColumn.set(myCatColumn.isEqualTo("Cat"), "Dog"); // no more cats myCatColumn.set(myCatColumn.valueIsMissing(), "Fox"); // no more missing values

Specified by:

set in interface Column<String>

Overrides:

set in class AbstractColumn<StringColumn,String>

set

public StringColumn set(int rowIndex,
                        String stringValue)

countUnique

public int countUnique()

Description copied from interface: Column

Returns the count of unique values in this column.

Returns:

unique values as int

contains

public boolean contains(String aString)

Returns true if this column contains a cell with the given string, and false otherwise

Parameters:

aString - the value to look for

Returns:

true if contains, false otherwise

setMissing

public Column<String> setMissing(int i)

addAll

public StringColumn addAll(List<String> stringValues)

Add all the strings in the list to this column

Parameters:

stringValues - a list of values

appendCell

public StringColumn appendCell(String object)

appendCell

public StringColumn appendCell(String object,
                               AbstractColumnParser<?> parser)

rowComparator

public it.unimi.dsi.fastutil.ints.IntComparator rowComparator()

isEmpty

public boolean isEmpty()

Description copied from interface: Column

Returns true if the column has no data

Returns:

true if empty, false if not

isEqualTo

public Selection isEqualTo(String string)

isNotEqualTo

public Selection isNotEqualTo(String string)

getDummies

public List<BooleanColumn> getDummies()

Returns a list of boolean columns suitable for use as dummy variables in, for example, regression analysis, select a column of categorical data must be encoded as a list of columns, such that each column represents a single category and indicates whether it is present (1) or not present (0)

Returns:

a list of BooleanColumn

unique

public StringColumn unique()

Returns a new Column containing all the unique values in this column

Returns:

a column with unique values.

asDoubleColumn

public DoubleColumn asDoubleColumn()

where

public StringColumn where(Selection selection)

copy

public StringColumn copy()

Description copied from interface: Column

Returns a deep copy of the receiver

Returns:

a Column

append

public StringColumn append(Column<String> column)

countMissing

public int countMissing()

Returns the count of missing values in this column

Returns:

missing values as int

removeMissing

public StringColumn removeMissing()

iterator

public Iterator<String> iterator()

asSet

public Set<String> asSet()

asBytes

public 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[]

getDouble

public double getDouble(int i)

asDoubleArray

public double[] asDoubleArray()

append

public StringColumn append(String value)

Added for naming consistency with all other columns

appendObj

public StringColumn appendObj(Object obj)

isIn

public Selection isIn(String... strings)

isIn

public Selection isIn(Collection<String> strings)

isNotIn

public Selection isNotIn(String... strings)

isNotIn

public Selection isNotIn(Collection<String> strings)

firstIndexOf

public int firstIndexOf(String value)

countOccurrences

public int countOccurrences(String value)

asObjectArray

public String[] asObjectArray()

asStringColumn

public StringColumn asStringColumn()

Description copied from interface: Column

Returns a StringColumn consisting of the (unformatted) String representation of this column values

Specified by:

asStringColumn in interface Column<String>

Overrides:

asStringColumn in class AbstractColumn<StringColumn,String>

Returns:

a StringColumn built using the column Column.getUnformattedString(int) method

asTextColumn

public TextColumn asTextColumn()

getLookupTable

public LookupTableWrapper getLookupTable()

For tablesaw internal use only