Package stdlib

Class StdStats

java.lang.Object

stdlib.StdStats

public final class StdStats
extends Object

Standard statistics. This class provides methods for computing statistics such as min, max, mean, sample standard deviation, and sample variance.

For additional documentation, see Section 2.2 of Introduction to Programming in Java: An Interdisciplinary Approach by Robert Sedgewick and Kevin Wayne.

Method Summary

Modifier and Type	Method	Description
static void	main(String[] args)	Test client.
static double	max(double[] a)	Return maximum value in array, -infinity if no such value.
static double	max(double[] a, int lo, int hi)	Return maximum value in subarray a[lo..hi], -infinity if no such value.
static int	max(int[] a)	Return maximum value of array, Integer.MIN_VALUE if no such value
static double	mean(double[] a)	Return average value in array, NaN if no such value.
static double	mean(double[] a, int lo, int hi)	Return average value in subarray a[lo..hi], NaN if no such value.
static double	mean(int[] a)	Return average value in array, NaN if no such value.
static double	min(double[] a)	Return minimum value in array, +infinity if no such value.
static double	min(double[] a, int lo, int hi)	Return minimum value in subarray a[lo..hi], +infinity if no such value.
static int	min(int[] a)	Return minimum value of array, Integer.MAX_VALUE if no such value
static void	plotBars(double[] a)	Plot bars from (0, a[i]) to (i, a[i]) to standard draw.
static void	plotLines(double[] a)	Plot line segments connecting points (i, a[i]) to standard draw.
static void	plotPoints(double[] a)	Plot points (i, a[i]) to standard draw.
static double	stddev(double[] a)	Return sample standard deviation of array, NaN if no such value.
static double	stddev(double[] a, int lo, int hi)	Return sample standard deviation of subarray a[lo..hi], NaN if no such value.
static double	stddev(int[] a)	Return sample standard deviation of array, NaN if no such value.
static double	stddevp(double[] a)	Return population standard deviation of array, NaN if no such value.
static double	stddevp(double[] a, int lo, int hi)	Return population standard deviation of subarray a[lo..hi], NaN if no such value.
static double	sum(double[] a)	Return sum of all values in array.
static double	sum(double[] a, int lo, int hi)	Return sum of all values in subarray a[lo..hi].
static int	sum(int[] a)	Return sum of all values in array.
static double	var(double[] a)	Return sample variance of array, NaN if no such value.
static double	var(double[] a, int lo, int hi)	Return sample variance of subarray a[lo..hi], NaN if no such value.
static double	var(int[] a)	Return sample variance of array, NaN if no such value.
static double	varp(double[] a)	Return population variance of array, NaN if no such value.
static double	varp(double[] a, int lo, int hi)	Return population variance of subarray a[lo..hi], NaN if no such value.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

max

public static double max(double[] a)

Return maximum value in array, -infinity if no such value.

max

public static double max(double[] a,
 int lo,
 int hi)

Return maximum value in subarray a[lo..hi], -infinity if no such value.

max

public static int max(int[] a)

Return maximum value of array, Integer.MIN_VALUE if no such value

min

public static double min(double[] a)

Return minimum value in array, +infinity if no such value.

min

public static double min(double[] a,
 int lo,
 int hi)

Return minimum value in subarray a[lo..hi], +infinity if no such value.

min

public static int min(int[] a)

Return minimum value of array, Integer.MAX_VALUE if no such value

mean

public static double mean(double[] a)

Return average value in array, NaN if no such value.

mean

public static double mean(double[] a,
 int lo,
 int hi)

Return average value in subarray a[lo..hi], NaN if no such value.

mean

public static double mean(int[] a)

Return average value in array, NaN if no such value.

var

public static double var(double[] a)

Return sample variance of array, NaN if no such value.

var

public static double var(double[] a,
 int lo,
 int hi)

Return sample variance of subarray a[lo..hi], NaN if no such value.

var

public static double var(int[] a)

Return sample variance of array, NaN if no such value.

varp

public static double varp(double[] a)

Return population variance of array, NaN if no such value.

varp

public static double varp(double[] a,
 int lo,
 int hi)

Return population variance of subarray a[lo..hi], NaN if no such value.

stddev

public static double stddev(double[] a)

Return sample standard deviation of array, NaN if no such value.

stddev

public static double stddev(double[] a,
 int lo,
 int hi)

Return sample standard deviation of subarray a[lo..hi], NaN if no such value.

stddev

public static double stddev(int[] a)

Return sample standard deviation of array, NaN if no such value.

stddevp

public static double stddevp(double[] a)

Return population standard deviation of array, NaN if no such value.

stddevp

public static double stddevp(double[] a,
 int lo,
 int hi)

Return population standard deviation of subarray a[lo..hi], NaN if no such value.

sum

public static double sum(double[] a)

Return sum of all values in array.

sum

public static double sum(double[] a,
 int lo,
 int hi)

Return sum of all values in subarray a[lo..hi].

sum

public static int sum(int[] a)

Return sum of all values in array.

plotPoints

public static void plotPoints(double[] a)

Plot points (i, a[i]) to standard draw.

plotLines

public static void plotLines(double[] a)

Plot line segments connecting points (i, a[i]) to standard draw.

plotBars

public static void plotBars(double[] a)

Plot bars from (0, a[i]) to (i, a[i]) to standard draw.

main

public static void main(String[] args)

Test client. Convert command-line arguments to array of doubles and call various methods.