StringColumn (tablesaw-core 0.21.0 API)

java.lang.Object
- tech.tablesaw.columns.AbstractColumn
- - tech.tablesaw.api.StringColumn

All Implemented Interfaces:

Iterable<String>, CategoricalColumn, Column, StringFilters, StringMapFunctions, StringReduceUtils
```
public class StringColumn
extends AbstractColumn
implements CategoricalColumn, StringFilters, StringMapFunctions, StringReduceUtils
```
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
Modifier and Type Field Description

StringColumnReference column

static String MISSING_VALUE
- Fields inherited from class tech.tablesaw.columns.AbstractColumn
  DEFAULT_ARRAY_SIZE

Fields
Modifier and Type	Field	Description
`StringColumnReference`	`column`
`static String`	`MISSING_VALUE`

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`StringColumn`	`addAll(List<String> stringValues)`	Add all the strings in the list to this column
`StringColumn`	`append(String value)`	Added for naming consistency with all other columns
`void`	`append(Column column)`
`StringColumn`	`appendCell(String object)`
`StringColumn`	`appendMissing()`	Appends a missing value appropriate to the column
`byte[]`	`asBytes(int rowNumber)`	Returns the contents of the cell at rowNumber as a byte[]
`double[]`	`asDoubleArray()`
`List<String>`	`asList()`	Returns a List<String> representation of all the values in this column
`NumberColumn`	`asNumberColumn()`
`Set<String>`	`asSet()`
`List<String>`	`bottom(int n)`	Returns the smallest ("bottom") n values in the column
`int`	`byteSize()`	Returns the width of a cell in this column, in bytes.
`void`	`clear()`
`boolean`	`contains(String aString)`	Returns true if this column contains a cell with the given string, and false otherwise
`static String`	`convert(String stringValue)`
`StringColumn`	`copy()`	Returns a deep copy of the receiver
`Table`	`countByCategory()`
`int`	`countMissing()`	Returns the count of missing values in this column
`double`	`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, String[] strings)`
`static StringColumn`	`create(String name, List<String> strings)`
`it.unimi.dsi.fastutil.ints.IntArrayList`	`data()`	Returns the integers that back this column.
`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)`	Returns a double representation of the value at the given row.
`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)
`StringColumnFormatter`	`getPrintFormatter()`
`String`	`getString(int row)`	Returns a string representation of the value at the given row.
`String`	`getUnformattedString(int row)`
`it.unimi.dsi.fastutil.ints.IntArrayList`	`getValues(it.unimi.dsi.fastutil.ints.IntArrayList indexes)`	Returns all the values associated with the given indexes.
`void`	`initializeWith(it.unimi.dsi.fastutil.ints.IntArrayList list, StringColumn old)`	Initializes this Column with the given values for performance
`boolean`	`isEmpty()`	Returns true if the column has no data
`Selection`	`isEqualTo(String string)`
`Selection`	`isIn(String... strings)`
`boolean`	`isMissing(int rowNumber)`
`Selection`	`isNotEqualTo(String string)`
`Selection`	`isNotIn(String... strings)`
`Iterator<String>`	`iterator()`
`it.unimi.dsi.fastutil.ints.Int2ObjectMap<String>`	`keyToValueMap()`
`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(String newValue, Selection rowSelection)`	Conditionally update this column, replacing current values with newValue for all rows where the current value matches the selection criteria
`void`	`setPrintFormatter(StringColumnFormatter formatter)`
`int`	`size()`	Returns the number of elements (a.k.a.
`void`	`sortAscending()`
`void`	`sortDescending()`
`Table`	`summary()`
`List<String>`	`top(int n)`	Returns the largest ("top") n values in the column
`ColumnType`	`type()`	Returns this column's ColumnType
`StringColumn`	`unique()`	Returns a new Column containing all the unique values in this column
`static boolean`	`valueIsMissing(String string)`
`it.unimi.dsi.fastutil.ints.IntArrayList`	`values()`	Returns the integer encoded value of each cell in this column.
`StringColumn`	`where(Filter filter)`
`StringColumn`	`where(Selection selection)`

Methods inherited from class tech.tablesaw.columns.AbstractColumn
columnWidth, name, print, setName, toString

Methods inherited from interface tech.tablesaw.columns.Column
columnWidth, create, first, inRange, last, name, print, rolling, rows, sampleN, sampleX, setName, subset, summarizeIf, title

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

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, isIn, isLongerThan, isLowerCase, isMissing, isNotEqualTo, isNotIn, isNotMissing, isNumeric, isShorterThan, isUpperCase, lengthEquals, matchesRegex, startsWith

Methods inherited from interface tech.tablesaw.columns.strings.StringMapFunctions
abbreviate, commonPrefix, commonSuffix, concatenate, countTokens, distance, format, join, length, lowerCase, padEnd, padStart, replaceAll, replaceAll, replaceFirst, substring, substring, tokenizeAndRemoveDuplicates, tokenizeAndSort, tokenizeAndSort, tokens, trim, uniqueTokens, upperCase

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

- Field Detail
  - column
```
public final StringColumnReference column
```
  - MISSING_VALUE
```
public static final String MISSING_VALUE
```
- 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
    
    Specified by:
    
    appendMissing in interface 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)
```
  - create
```
public static StringColumn create(String name,
                                  int size)
```
  - convert
```
public static String convert(String stringValue)
```
  - isMissing
```
public boolean isMissing(int rowNumber)
```
    Specified by:
    
    isMissing in interface Column
  - type
```
public ColumnType type()
```
    Description copied from interface: Column
    
    Returns this column's ColumnType
    
    Specified by:
    
    type in interface Column
    
    Overrides:
    
    type in class AbstractColumn
    
    Returns:
    
    ColumnType
  - setPrintFormatter
```
public void setPrintFormatter(StringColumnFormatter formatter)
```
  - getPrintFormatter
```
public StringColumnFormatter getPrintFormatter()
```
  - getString
```
public String getString(int row)
```
    Description copied from interface: Column
    
    Returns a string representation of the value at the given row.
    
    Specified by:
    
    getString in interface Column
    
    Parameters:
    
    row - The index of the row.
    
    Returns:
    
    value as String
  - getUnformattedString
```
public String getUnformattedString(int row)
```
    Specified by:
    
    getUnformattedString in interface Column
  - 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
    
    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.
    
    Specified by:
    
    emptyCopy in interface Column
    
    Parameters:
    
    rowSize - the initial row size
    
    Returns:
    
    a Column
  - sortAscending
```
public void sortAscending()
```
    Specified by:
    
    sortAscending in interface Column
  - sortDescending
```
public void sortDescending()
```
    Specified by:
    
    sortDescending in interface Column
  - size
```
public int size()
```
    Returns the number of elements (a.k.a. rows or cells) in the column
    
    Specified by:
    
    size in interface Column
    
    Returns:
    
    size as int
  - get
```
public String get(int rowIndex)
```
    Returns the value at rowIndex in this column. The index is zero-based.
    
    Specified by:
    
    get in interface StringFilters
    
    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()
```
    Specified by:
    
    summary in interface Column
  - countByCategory
```
public Table countByCategory()
```
    Specified by:
    
    countByCategory in interface CategoricalColumn
  - clear
```
public void clear()
```
    Specified by:
    
    clear in interface Column
  - 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.
    
    Specified by:
    
    lead in interface Column
  - 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
    
    Specified by:
    
    lag in interface Column
  - set
```
public StringColumn set(String newValue,
                        Selection rowSelection)
```
    Conditionally update this column, replacing current values with newValue for all rows where the current value matches the selection criteria
    Examples: myCatColumn.set("Dog", myCatColumn.isEqualTo("Cat")); // no more cats myCatColumn.set("Fox", myCatColumn.valueIsMissing()); // no more missing values
  - 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.
    
    Specified by:
    
    countUnique in interface Column
    
    Returns:
    
    unique values as int
  - top
```
public List<String> top(int n)
```
    Returns the largest ("top") n values in the column
    
    Parameters:
    
    n - The maximum number of records to return. The actual number will be smaller if n is greater than the number of observations in the column
    
    Returns:
    
    A list, possibly empty, of the largest observations
  - bottom
```
public List<String> bottom(int n)
```
    Returns the smallest ("bottom") n values in the column
    
    Parameters:
    
    n - The maximum number of records to return. The actual number will be smaller if n is greater than the number of observations in the column
    
    Returns:
    
    A list, possibly empty, of the smallest n observations
  - initializeWith
```
public void initializeWith(it.unimi.dsi.fastutil.ints.IntArrayList list,
                           StringColumn old)
```
    Initializes this Column with the given values for performance
  - 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
  - getValues
```
public it.unimi.dsi.fastutil.ints.IntArrayList getValues(it.unimi.dsi.fastutil.ints.IntArrayList indexes)
```
    Returns all the values associated with the given indexes.
    
    Parameters:
    
    indexes - the indexes
    
    Returns:
    
    values as IntArrayList
  - 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)
```
    Specified by:
    
    appendCell in interface Column
    
    Specified by:
    
    appendCell in class AbstractColumn
  - rowComparator
```
public it.unimi.dsi.fastutil.ints.IntComparator rowComparator()
```
    Specified by:
    
    rowComparator in interface Column
  - isEmpty
```
public boolean isEmpty()
```
    Description copied from interface: Column
    
    Returns true if the column has no data
    
    Specified by:
    
    isEmpty in interface Column
    
    Returns:
    
    true if empty, false if not
  - isEqualTo
```
public Selection isEqualTo(String string)
```
    Specified by:
    
    isEqualTo in interface StringFilters
  - 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
    
    Specified by:
    
    unique in interface Column
    
    Returns:
    
    a column with unique values.
  - data
```
public it.unimi.dsi.fastutil.ints.IntArrayList data()
```
    Returns the integers that back this column.
    
    Returns:
    
    data as IntArrayList
  - asNumberColumn
```
public NumberColumn asNumberColumn()
```
  - where
```
public StringColumn where(Selection selection)
```
    Specified by:
    
    where in interface Column
  - where
```
public StringColumn where(Filter filter)
```
    Specified by:
    
    where in interface StringFilters
  - copy
```
public StringColumn copy()
```
    Description copied from interface: Column
    
    Returns a deep copy of the receiver
    
    Specified by:
    
    copy in interface Column
    
    Returns:
    
    a Column
  - append
```
public void append(Column column)
```
    Specified by:
    
    append in interface Column
  - countMissing
```
public int countMissing()
```
    Returns the count of missing values in this column
    
    Specified by:
    
    countMissing in interface Column
    
    Returns:
    
    missing values as int
  - removeMissing
```
public StringColumn removeMissing()
```
    Specified by:
    
    removeMissing in interface Column
  - iterator
```
public Iterator<String> iterator()
```
    Specified by:
    
    iterator in interface Iterable<String>
  - asSet
```
public Set<String> asSet()
```
  - values
```
public it.unimi.dsi.fastutil.ints.IntArrayList values()
```
    Returns the integer encoded value of each cell in this column. It can be used to lookup the mapped string in the lookupTable TODO(lwhite): Should this be private?
    
    Returns:
    
    values a IntArrayList
  - byteSize
```
public int byteSize()
```
    Description copied from interface: Column
    
    Returns the width of a cell in this column, in bytes.
    
    Specified by:
    
    byteSize in interface Column
    
    Returns:
    
    width in bytes
  - asBytes
```
public byte[] asBytes(int rowNumber)
```
    Returns the contents of the cell at rowNumber as a byte[]
    
    Specified by:
    
    asBytes in interface Column
    
    Parameters:
    
    rowNumber - index of the row
    
    Returns:
    
    content as byte[]
  - getDouble
```
public double getDouble(int i)
```
    Description copied from interface: Column
    
    Returns a double representation of the value at the given row. The nature of the returned value is column-specific. The double returned MAY be the actual value (for Number columns) but is more likely a number that maps to the column value in some way.
    
    Specified by:
    
    getDouble in interface Column
    
    Parameters:
    
    i - The index of the row.
    
    Returns:
    
    value as String
  - asDoubleArray
```
public double[] asDoubleArray()
```
    Specified by:
    
    asDoubleArray in interface Column
  - append
```
public StringColumn append(String value)
```
    Added for naming consistency with all other columns
  - isIn
```
public Selection isIn(String... strings)
```
    Specified by:
    
    isIn in interface StringFilters
  - isNotIn
```
public Selection isNotIn(String... strings)
```
    Specified by:
    
    isNotIn in interface StringFilters
  - keyToValueMap
```
public it.unimi.dsi.fastutil.ints.Int2ObjectMap<String> keyToValueMap()
```
  - firstIndexOf
```
public int firstIndexOf(String value)
```
  - countOccurrences
```
public double countOccurrences(String value)
```

Class StringColumn

Field Summary

Fields inherited from class tech.tablesaw.columns.AbstractColumn

Method Summary

Methods inherited from class tech.tablesaw.columns.AbstractColumn

Methods inherited from interface tech.tablesaw.columns.Column

Methods inherited from interface java.lang.Iterable

Methods inherited from class java.lang.Object

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

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

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

Field Detail

column

MISSING_VALUE

Method Detail

valueIsMissing

appendMissing

create

create

create

create

convert

isMissing

type

setPrintFormatter

getPrintFormatter

getString

getUnformattedString

emptyCopy

emptyCopy

sortAscending

sortDescending

size

get

asList

summary

countByCategory

clear

lead

lag

set

set

countUnique

top

bottom

initializeWith

contains

getValues

addAll

appendCell

rowComparator

isEmpty

isEqualTo

isNotEqualTo

getDummies

unique

data

asNumberColumn

where

where

copy

append

countMissing

removeMissing

iterator

asSet

values

byteSize

asBytes

getDouble

asDoubleArray

append

isIn

isNotIn

keyToValueMap

firstIndexOf

countOccurrences