Package org.hipparchus.stat

Class Frequency<T extends Comparable<T>>

java.lang.Object

org.hipparchus.stat.Frequency<T>

Type Parameters:

T - the element type

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

LongFrequency

public class Frequency<T extends Comparable<T>>
extends Object
implements Serializable

Maintains a frequency distribution of Comparable values.

The values are ordered using the default (natural order), unless a Comparator is supplied in the constructor.

See Also:

LongFrequency, Serialized Form

Constructor Summary

Constructors

Constructor	Description
Frequency()	Default constructor.
Frequency(Comparator<? super T> comparator)	Constructor allowing values Comparator to be specified.

Method Summary

Modifier and Type	Method	Description
void	addValue(T v)	Adds 1 to the frequency count for v.
void	clear()	Clears the frequency table
Iterator<Map.Entry<T,Long>>	entrySetIterator()	Return an Iterator over the set of keys and values that have been added.
boolean	equals(Object obj)
long	getCount(T v)	Returns the number of values equal to v.
long	getCumFreq(T v)	Returns the cumulative frequency of values less than or equal to v.
double	getCumPct(T v)	Returns the cumulative percentage of values less than or equal to v (as a proportion between 0 and 1).
List<T>	getMode()	Returns the mode value(s) in comparator order.
double	getPct(T v)	Returns the percentage of values that are equal to v (as a proportion between 0 and 1).
long	getSumFreq()	Returns the sum of all frequencies.
int	getUniqueCount()	Returns the number of values in the frequency table.
int	hashCode()
void	incrementValue(T v, long increment)	Increments the frequency count for v.
void	merge(Collection<? extends Frequency<? extends T>> others)	Merge a Collection of Frequency objects into this instance.
void	merge(Frequency<? extends T> other)	Merge another Frequency object's counts into this instance.
String	toString()	Return a string representation of this frequency distribution.
Iterator<T>	valuesIterator()	Returns an Iterator over the set of values that have been added.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

Frequency

public Frequency()

Default constructor.

Frequency

public Frequency(Comparator<? super T> comparator)

Constructor allowing values Comparator to be specified.

Parameters:

comparator - Comparator used to order values

Method Detail

addValue

public void addValue(T v)

Adds 1 to the frequency count for v.

Parameters:

v - the value to add.

incrementValue

public void incrementValue(T v,
                           long increment)

Increments the frequency count for v.

Parameters:

v - the value to add.

increment - the amount by which the value should be incremented

clear

public void clear()

Clears the frequency table

valuesIterator

public Iterator<T> valuesIterator()

Returns an Iterator over the set of values that have been added.

Returns:

values Iterator

entrySetIterator

public Iterator<Map.Entry<T,Long>> entrySetIterator()

Return an Iterator over the set of keys and values that have been added. Using the entry set to iterate is more efficient in the case where you need to access respective counts as well as values, since it doesn't require a "get" for every key...the value is provided in the Map.Entry.

Returns:

entry set Iterator

getSumFreq

public long getSumFreq()

Returns the sum of all frequencies.

Returns:

the total frequency count.

getCount

public long getCount(T v)

Returns the number of values equal to v. Returns 0 if the value is not comparable.

Parameters:

v - the value to lookup.

Returns:

the frequency of v.

getUniqueCount

public int getUniqueCount()

Returns the number of values in the frequency table.

Returns:

the number of unique values that have been added to the frequency table.

See Also:

valuesIterator()

getPct

public double getPct(T v)

Returns the percentage of values that are equal to v (as a proportion between 0 and 1).

Returns Double.NaN if no values have been added.

Parameters:

v - the value to lookup

Returns:

the proportion of values equal to v

getCumFreq

public long getCumFreq(T v)

Returns the cumulative frequency of values less than or equal to v.

Parameters:

v - the value to lookup.

Returns:

the proportion of values equal to v

getCumPct

public double getCumPct(T v)

Returns the cumulative percentage of values less than or equal to v (as a proportion between 0 and 1).

Returns Double.NaN if no values have been added.

Parameters:

v - the value to lookup

Returns:

the proportion of values less than or equal to v

getMode

public List<T> getMode()

Returns the mode value(s) in comparator order.

Returns:

a list containing the value(s) which appear most often.

merge

public void merge(Frequency<? extends T> other)
           throws NullArgumentException

Merge another Frequency object's counts into this instance. This Frequency's counts will be incremented (or set when not already set) by the counts represented by other.

Parameters:

other - the other Frequency object to be merged

Throws:

NullArgumentException - if other is null

merge

public void merge(Collection<? extends Frequency<? extends T>> others)
           throws NullArgumentException

Merge a Collection of Frequency objects into this instance. This Frequency's counts will be incremented (or set when not already set) by the counts represented by each of the others.

Parameters:

others - the other Frequency objects to be merged

Throws:

NullArgumentException - if the collection is null

toString

public String toString()

Return a string representation of this frequency distribution.

Overrides:

toString in class Object

Returns:

a string representation.

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object obj)

Overrides:

equals in class Object