ColumnReference (tablesaw-core 0.9.0 API)

java.lang.Object
- tech.tablesaw.columns.ColumnReference

```
public class ColumnReference
extends Object
```
A reference to a column that can be used in evaluating query predicates. It is a key part of having a fluent API for querying tables.
Basically, it lets you write a query like this:
table.selectWhere(column("foo").isEqualTo("Bar"));
In that example, column() is a static method that returns a ColumnReference for a column named "foo". The method isEqualTo(), is implemented on ColumnReference in a way that it can be applied to potentially, multiple column types, although in this case, it only makes sense for CategoryColumns since the argument is a string.
When selectWhere() isExecuted, it supplies the table to the ColumnReference. The ColumnReference uses the table and columnName to get access to the right column, and then fulfils its role by ensuring that the filtering "isEqualTo("Bar") is applied to all the cells in the column.

Constructor Summary

Constructors
Constructor and Description

ColumnReference(String column)

Constructors
Constructor and Description
`ColumnReference(String column)`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`Filter`	`contains(String string)`
`Filter`	`endsWith(String string)`
`Filter`	`equalToIgnoringCase(String string)`
`String`	`getColumnName()`
`Filter`	`hasLengthEqualTo(int length)`
`Filter`	`isAfter(LocalDate date)`
`Filter`	`isAfter(LocalDateTime value)`
`Filter`	`isAfter(LocalTime value)`
`Filter`	`isAfterNoon()`
`Filter`	`isAlpha()`
`Filter`	`isAlphaNumeric()`
`Filter`	`isBefore(LocalDate date)`
`Filter`	`isBefore(LocalDateTime value)`
`Filter`	`isBefore(LocalTime value)`
`Filter`	`isBeforeNoon()`
`Filter`	`isBetween(int low, int high)`
`Filter`	`isBetween(LocalDate low, LocalDate high)`
`Filter`	`isEmpty()`
`Filter`	`isEqualTo(ColumnReference reference)`
`Filter`	`isEqualTo(float value)`
`Filter`	`isEqualTo(int value)`
`Filter`	`isEqualTo(LocalDate value)`
`Filter`	`isEqualTo(LocalTime value)`
`Filter`	`isEqualTo(String value)`
`Filter`	`isFalse()`
`Filter`	`isFirstDayOfMonth()`
`Filter`	`isFriday()`
`Filter`	`isGreaterThan(float value)`
`Filter`	`isGreaterThan(int value)`
`Filter`	`isGreaterThanOrEqualTo(float value)`
`Filter`	`isGreaterThanOrEqualTo(int value)`
`Filter`	`isIn(int... ints)`
`Filter`	`isIn(IntColumn intColumn)`
`Filter`	`isIn(String... strings)`
`Filter`	`isInApril()`
`Filter`	`isInAugust()`
`Filter`	`isInDecember()`
`Filter`	`isInFebruary()`
`Filter`	`isInJanuary()`
`Filter`	`isInJuly()`
`Filter`	`isInJune()`
`Filter`	`isInMarch()`
`Filter`	`isInMay()`
`Filter`	`isInNovember()`
`Filter`	`isInOctober()`
`Filter`	`isInQ1()`
`Filter`	`isInQ2()`
`Filter`	`isInQ3()`
`Filter`	`isInQ4()`
`Filter`	`isInSeptember()`
`Filter`	`isInYear(int year)`
`Filter`	`isLastDayOfMonth()`
`Filter`	`isLessThan(float value)`
`Filter`	`isLessThan(int value)`
`Filter`	`isLessThanOrEqualTo(float value)`
`Filter`	`isLessThanOrEqualTo(int value)`
`Filter`	`isLongerThan(int length)`
`Filter`	`isLowerCase()`
`Filter`	`isMidnight()`
`Filter`	`isMissing()`
`Filter`	`isMonday()`
`Filter`	`isNoon()`
`Filter`	`isNotEqualTo(LocalTime value)`
`Filter`	`isNotEqualTo(String value)`
`Filter`	`isNotMissing()`
`Filter`	`isNumeric()`
`Filter`	`isSaturday()`
`Filter`	`isShorterThan(int length)`
`Filter`	`isSunday()`
`Filter`	`isThursday()`
`Filter`	`isTrue()`
`Filter`	`isTuesday()`
`Filter`	`isUpperCase()`
`Filter`	`isWednesday()`
`Filter`	`matchesRegex(String string)`
`Filter`	`startsWith(String string)`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail
- ColumnReference
```
public ColumnReference(String column)
```

Method Detail

isNotMissing
```
public Filter isNotMissing()
```

isMissing
```
public Filter isMissing()
```

isEqualTo
```
public Filter isEqualTo(int value)
```

isEqualTo

public Filter isEqualTo(ColumnReference reference)

isBetween

public Filter isBetween(int low,
                        int high)

isBetween

public Filter isBetween(LocalDate low,
                        LocalDate high)

isEqualTo
```
public Filter isEqualTo(float value)
```

isEqualTo

public Filter isEqualTo(LocalTime value)

isNotEqualTo

public Filter isNotEqualTo(LocalTime value)

isEqualTo

public Filter isEqualTo(LocalDate value)

isEqualTo

public Filter isEqualTo(String value)

isNotEqualTo

public Filter isNotEqualTo(String value)

isGreaterThan

public Filter isGreaterThan(int value)

isIn

public Filter isIn(IntColumn intColumn)

isIn

public Filter isIn(String... strings)

isIn
```
public Filter isIn(int... ints)
```

isLessThan
```
public Filter isLessThan(int value)
```

isLessThanOrEqualTo

public Filter isLessThanOrEqualTo(int value)

isGreaterThanOrEqualTo

public Filter isGreaterThanOrEqualTo(int value)

isGreaterThan

public Filter isGreaterThan(float value)

isLessThan

public Filter isLessThan(float value)

isLessThanOrEqualTo

public Filter isLessThanOrEqualTo(float value)

isGreaterThanOrEqualTo

public Filter isGreaterThanOrEqualTo(float value)

getColumnName
```
public String getColumnName()
```

isMidnight
```
public Filter isMidnight()
```

isNoon
```
public Filter isNoon()
```

isBeforeNoon
```
public Filter isBeforeNoon()
```

isAfterNoon
```
public Filter isAfterNoon()
```

isBefore

public Filter isBefore(LocalTime value)

isBefore

public Filter isBefore(LocalDateTime value)

isAfter

public Filter isAfter(LocalDateTime value)

isAfter

public Filter isAfter(LocalTime value)

isSunday
```
public Filter isSunday()
```

isMonday
```
public Filter isMonday()
```

isTuesday
```
public Filter isTuesday()
```

isWednesday
```
public Filter isWednesday()
```

isThursday
```
public Filter isThursday()
```

isFriday
```
public Filter isFriday()
```

isSaturday
```
public Filter isSaturday()
```

isInJanuary
```
public Filter isInJanuary()
```

isInFebruary
```
public Filter isInFebruary()
```

isInMarch
```
public Filter isInMarch()
```

isInApril
```
public Filter isInApril()
```

isInMay
```
public Filter isInMay()
```

isInJune
```
public Filter isInJune()
```

isInJuly
```
public Filter isInJuly()
```

isInAugust
```
public Filter isInAugust()
```

isInSeptember
```
public Filter isInSeptember()
```

isInOctober
```
public Filter isInOctober()
```

isInNovember
```
public Filter isInNovember()
```

isInDecember
```
public Filter isInDecember()
```

isInQ1
```
public Filter isInQ1()
```

isInQ2
```
public Filter isInQ2()
```

isInQ3
```
public Filter isInQ3()
```

isInQ4
```
public Filter isInQ4()
```

isFirstDayOfMonth
```
public Filter isFirstDayOfMonth()
```

isLastDayOfMonth
```
public Filter isLastDayOfMonth()
```

isInYear
```
public Filter isInYear(int year)
```

isBefore

public Filter isBefore(LocalDate date)

isAfter

public Filter isAfter(LocalDate date)

isUpperCase
```
public Filter isUpperCase()
```

isLowerCase
```
public Filter isLowerCase()
```

isAlpha
```
public Filter isAlpha()
```

isAlphaNumeric
```
public Filter isAlphaNumeric()
```

isNumeric
```
public Filter isNumeric()
```

isEmpty
```
public Filter isEmpty()
```

isLongerThan

public Filter isLongerThan(int length)

isShorterThan

public Filter isShorterThan(int length)

hasLengthEqualTo

public Filter hasLengthEqualTo(int length)

equalToIgnoringCase

public Filter equalToIgnoringCase(String string)

startsWith

public Filter startsWith(String string)

endsWith

public Filter endsWith(String string)

contains

public Filter contains(String string)

matchesRegex

public Filter matchesRegex(String string)

isTrue
```
public Filter isTrue()
```

isFalse
```
public Filter isFalse()
```

Class ColumnReference

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

ColumnReference

Method Detail

isNotMissing

isMissing

isEqualTo

isEqualTo

isBetween

isBetween

isEqualTo

isEqualTo

isNotEqualTo

isEqualTo

isEqualTo

isNotEqualTo

isGreaterThan

isIn

isIn

isIn

isLessThan

isLessThanOrEqualTo

isGreaterThanOrEqualTo

isGreaterThan

isLessThan

isLessThanOrEqualTo

isGreaterThanOrEqualTo

getColumnName

isMidnight

isNoon

isBeforeNoon

isAfterNoon

isBefore

isBefore

isAfter

isAfter

isSunday

isMonday

isTuesday

isWednesday

isThursday

isFriday

isSaturday

isInJanuary

isInFebruary

isInMarch

isInApril

isInMay

isInJune

isInJuly

isInAugust

isInSeptember

isInOctober

isInNovember

isInDecember

isInQ1

isInQ2

isInQ3

isInQ4

isFirstDayOfMonth

isLastDayOfMonth

isInYear

isBefore

isAfter

isUpperCase

isLowerCase

isAlpha

isAlphaNumeric

isNumeric

isEmpty

isLongerThan

isShorterThan

hasLengthEqualTo

equalToIgnoringCase

startsWith

endsWith

contains