java.lang.Object
- weka.core.Utils

All Implemented Interfaces:

RevisionHandler
```
public final class Utils
extends java.lang.Object
implements RevisionHandler
```
Class implementing some simple utility methods.

Version:

$Revision: 15305 $

Author:

Eibe Frank, Yong Wang, Len Trigg, Julien Prados

Field Summary

Fields
Modifier and Type Field Description

static double log2
The natural logarithm of 2.

static double SMALL
The small deviation allowed in double comparisons.

Constructor Summary

Constructors
Constructor Description

Utils()

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`static java.lang.String`	`arrayToString(java.lang.Object array)`	Returns the given Array in a string representation.
`static java.lang.String`	`backQuoteChars(java.lang.String string)`	Converts carriage returns and new lines in a string into \r and \n.
`static java.lang.String[]`	`breakUp(java.lang.String s, int columns)`	Breaks up the string, if wider than "columns" characters.
`static <T> T`	`cast(java.lang.Object x)`	Casting an object without "unchecked" compile-time warnings.
`static void`	`checkForRemainingOptions(java.lang.String[] options)`	Checks if the given array contains any non-empty options.
`static Range`	`configureRangeFromRangeStringOrAttributeNameList(Instances instanceInfo, java.lang.String rangeString)`	Returns a configured Range object given a 1-based range index string (such as 1-20,35,last) or a comma-separated list of attribute names.
`static java.lang.String`	`convertNewLines(java.lang.String string)`	Converts carriage returns and new lines in a string into \r and \n.
`static java.io.File`	`convertToRelativePath(java.io.File absolute)`	Converts a File's absolute path to a path relative to the user (ie start) directory.
`static double`	`correlation(double[] y1, double[] y2, int n)`	Returns the correlation coefficient of two double vectors.
`static double`	`dateToMillis(java.lang.String dateString, java.lang.String dateFormat)`	Turns a given date string into Java's internal representation (milliseconds from 1 January 1970).
`static java.lang.String`	`doubleToString(double value, int afterDecimalPoint)`	Rounds a double and converts it into String.
`static java.lang.String`	`doubleToString(double value, int width, int afterDecimalPoint)`	Rounds a double and converts it into a formatted decimal-justified String.
`static boolean`	`eq(double a, double b)`	Tests if a is equal to b.
`static java.lang.Object`	`forName(java.lang.Class<?> classType, java.lang.String className, java.lang.String[] options)`	Creates a new instance of an object given it's class name and (optional) arguments to pass to it's setOptions method.
`static java.lang.Class<?>`	`getArrayClass(java.lang.Class<?> c)`	Returns the basic class of an array class (handles multi-dimensional arrays).
`static int`	`getArrayDimensions(java.lang.Class<?> array)`	Returns the dimensions of the given array.
`static int`	`getArrayDimensions(java.lang.Object array)`	Returns the dimensions of the given array.
`static boolean`	`getDontShowDialog(java.lang.String dialogName)`	For a named dialog, returns true if the user has opted not to view it again in the future.
`static java.lang.String`	`getDontShowDialogResponse(java.lang.String dialogName)`	For a named dialog, if the user has opted not to view it again, returns the answer the answer the user supplied when they closed the dialog.
`static boolean`	`getFlag(char flag, java.lang.String[] options)`	Checks if the given array contains the flag "-Char".
`static boolean`	`getFlag(java.lang.String flag, java.lang.String[] options)`	Checks if the given array contains the flag "-String".
`static java.lang.String`	`getGlobalInfo(java.lang.Object object, boolean addCapabilities)`	Utility method for grabbing the global info help (if it exists) from an arbitrary object.
`static java.lang.String`	`getOption(char flag, java.lang.String[] options)`	Gets an option indicated by a flag "-Char" from the given array of strings.
`static java.lang.String`	`getOption(java.lang.String flag, java.lang.String[] options)`	Gets an option indicated by a flag "-String" from the given array of strings.
`static int`	`getOptionPos(char flag, java.lang.String[] options)`	Gets the index of an option or flag indicated by a flag "-Char" from the given array of strings.
`static int`	`getOptionPos(java.lang.String flag, java.lang.String[] options)`	Gets the index of an option or flag indicated by a flag "-String" from the given array of strings.
`java.lang.String`	`getRevision()`	Returns the revision string.
`static javax.swing.JFrame`	`getWekaJFrame(java.lang.String title, java.awt.Component component)`	Returns a JFrame with the given title.
`static boolean`	`gr(double a, double b)`	Tests if a is greater than b.
`static boolean`	`grOrEq(double a, double b)`	Tests if a is greater or equal to b.
`static double`	`info(int[] counts)`	Computes entropy for an array of integers.
`static boolean`	`isMissingValue(double val)`	Tests if the given value codes "missing".
`static java.lang.String`	`joinOptions(java.lang.String[] optionArray)`	Joins all the options in an option array into a single string, as might be used on the command line.
`static double`	`kthSmallestValue(double[] array, int k)`	Returns the kth-smallest value in the array
`static int`	`kthSmallestValue(int[] array, int k)`	Returns the kth-smallest value in the array.
`static java.lang.String`	`lineWrap(java.lang.String input, int maxLineWidth)`	Implements simple line breaking.
`static double`	`log2(double a)`	Returns the logarithm of a for base 2.
`static double[]`	`logs2probs(double[] a)`	Converts an array containing the natural logarithms of probabilities stored in a vector back into probabilities.
`static void`	`main(java.lang.String[] ops)`	Main method for testing this class.
`static int`	`maxIndex(double[] doubles)`	Returns index of maximum element in a given array of doubles.
`static int`	`maxIndex(int[] ints)`	Returns index of maximum element in a given array of integers.
`static double`	`mean(double[] vector)`	Computes the mean for an array of doubles.
`static int`	`minIndex(double[] doubles)`	Returns index of minimum element in a given array of doubles.
`static int`	`minIndex(int[] ints)`	Returns index of minimum element in a given array of integers.
`static double`	`missingValue()`	Returns the value used to code a missing value.
`static void`	`normalize(double[] doubles)`	Normalizes the doubles in the array by their sum.
`static void`	`normalize(double[] doubles, double sum)`	Normalizes the doubles in the array using the given value.
`static java.lang.String`	`padLeft(java.lang.String inString, int length)`	Pads a string to a specified length, inserting spaces on the left as required.
`static java.lang.String`	`padLeftAndAllowOverflow(java.lang.String inString, int length)`	Pads a string to a specified length, inserting spaces on the left as required.
`static java.lang.String`	`padRight(java.lang.String inString, int length)`	Pads a string to a specified length, inserting spaces on the right as required.
`static java.lang.String`	`padRightAndAllowOverflow(java.lang.String inString, int length)`	Pads a string to a specified length, inserting spaces on the right as required.
`static java.lang.String[]`	`partitionOptions(java.lang.String[] options)`	Returns the secondary set of options (if any) contained in the supplied options array.
`static int`	`probRound(double value, java.util.Random rand)`	Rounds a double to the next nearest integer value in a probabilistic fashion (e.g.
`static double`	`probToLogOdds(double prob)`	Returns the log-odds for a given probabilitiy.
`static java.lang.String`	`quote(java.lang.String string)`	Quotes a string if it contains special characters.
`static java.util.Properties`	`readProperties(java.lang.String resourceName)`	Reads properties that inherit from three locations.
`static java.util.Properties`	`readProperties(java.lang.String resourceName, java.lang.ClassLoader loader)`	Reads properties that inherit from three locations.
`static java.lang.String`	`removeSubstring(java.lang.String inString, java.lang.String substring)`	Removes all occurrences of a string from another string.
`static void`	`replaceMissingWithMAX_VALUE(double[] array)`	Replaces all "missing values" in the given array of double values with MAX_VALUE.
`static java.lang.String`	`replaceStrings(java.lang.String string, java.lang.String[] charsFind, char[] charsReplace)`	Converts the specified strings in the given string to the specified characters.
`static java.lang.String`	`replaceSubstring(java.lang.String inString, java.lang.String subString, java.lang.String replaceString)`	Replaces with a new string, all occurrences of a string from another string.
`static java.lang.String`	`revertNewLines(java.lang.String string)`	Reverts \r and \n in a string into carriage returns and new lines.
`static int`	`round(double value)`	Rounds a double to the next nearest integer value.
`static double`	`roundDouble(double value, int afterDecimalPoint)`	Rounds a double to the given number of decimal places.
`static void`	`setDontShowDialog(java.lang.String dialogName)`	Specify that the named dialog is not to be displayed in the future.
`static void`	`setDontShowDialogResponse(java.lang.String dialogName, java.lang.String response)`	Specify that the named dialog is not to be shown again in the future.
`static boolean`	`sm(double a, double b)`	Tests if a is smaller than b.
`static boolean`	`smOrEq(double a, double b)`	Tests if a is smaller or equal to b.
`static int[]`	`sort(double[] array)`	Sorts a given array of doubles in ascending order and returns an array of integers with the positions of the elements of the original array in the sorted array.
`static int[]`	`sort(int[] array)`	Sorts a given array of integers in ascending order and returns an array of integers with the positions of the elements of the original array in the sorted array.
`static int[]`	`sortWithNoMissingValues(double[] array)`	Sorts a given array of doubles in ascending order and returns an array of integers with the positions of the elements of the original array in the sorted array.
`static java.lang.String[]`	`splitOptions(java.lang.String quotedOptionString)`	Split up a string containing options into an array of strings, one for each option.
`static java.lang.String[]`	`splitOptions(java.lang.String quotedOptionString, java.lang.String[] toReplace, char[] replacements)`	Split up a string containing options into an array of strings, one for each option.
`static int[]`	`stableSort(double[] array)`	Sorts a given array of doubles in ascending order and returns an array of integers with the positions of the elements of the original array in the sorted array.
`static double`	`sum(double[] doubles)`	Computes the sum of the elements of an array of doubles.
`static int`	`sum(int[] ints)`	Computes the sum of the elements of an array of integers.
`static int[]`	`takeSample(double[] weights, java.util.Random random)`	Takes a sample based on the given array of weights based on Walker's method.
`static java.lang.String`	`toCommandLine(java.lang.Object obj)`	Generates a commandline of the given object.
`static java.lang.String`	`unbackQuoteChars(java.lang.String string)`	The inverse operation of backQuoteChars().
`static java.lang.String`	`unquote(java.lang.String string)`	unquotes are previously quoted string (but only if necessary), i.e., it removes the single quotes around it.
`static double`	`variance(double[] vector)`	Computes the variance for an array of doubles.
`static double`	`xlogx(int c)`	Returns c*log2(c) for a given integer value c.

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

- Field Detail
  - log2
```
public static double log2
```
    The natural logarithm of 2.
  - SMALL
```
public static double SMALL
```
    The small deviation allowed in double comparisons.
- Constructor Detail
  - Utils
```
public Utils()
```
- Method Detail
  - dateToMillis
```
public static double dateToMillis(java.lang.String dateString,
                                  java.lang.String dateFormat)
                           throws java.text.ParseException
```
    Turns a given date string into Java's internal representation (milliseconds from 1 January 1970).
    
    Parameters:
    
    dateString - the string representing the date
    
    dateFormat - the date format as a string
    
    Returns:
    
    milliseconds since 1 January 1970 (as a double converted from long)
    
    Throws:
    
    java.text.ParseException
  - isMissingValue
```
public static boolean isMissingValue(double val)
```
    Tests if the given value codes "missing".
    
    Parameters:
    
    val - the value to be tested
    
    Returns:
    
    true if val codes "missing"
  - missingValue
```
public static double missingValue()
```
    Returns the value used to code a missing value. Note that equality tests on this value will always return false, so use isMissingValue(double val) for testing..
    
    Returns:
    
    the value used as missing value.
  - cast
```
public static <T> T cast(java.lang.Object x)
```
    Casting an object without "unchecked" compile-time warnings. Use only when absolutely necessary (e.g. when using clone()).
  - readProperties
```
public static java.util.Properties readProperties(java.lang.String resourceName)
                                           throws java.lang.Exception
```
    Reads properties that inherit from three locations. Properties are first defined in the system resource location (i.e. in the CLASSPATH). These default properties must exist. Properties optionally defined in the user properties location (WekaPackageManager.PROPERTIES_DIR) override default settings. Properties defined in the current directory (optional) override all these settings.
    
    Parameters:
    
    resourceName - the location of the resource that should be loaded. e.g.: "weka/core/Utils.props". (The use of hardcoded forward slashes here is OK - see jdk1.1/docs/guide/misc/resources.html) This routine will also look for the file (in this case) "Utils.props" in the users home directory and the current directory.
    
    Returns:
    
    the Properties
    
    Throws:
    
    java.lang.Exception - if no default properties are defined, or if an error occurs reading the properties files.
  - readProperties
```
public static java.util.Properties readProperties(java.lang.String resourceName,
                                                  java.lang.ClassLoader loader)
                                           throws java.lang.Exception
```
    Reads properties that inherit from three locations. Properties are first defined in the system resource location (i.e. in the CLASSPATH). These default properties must exist. Properties optionally defined in the user properties location (WekaPackageManager.PROPERTIES_DIR) override default settings. Properties defined in the current directory (optional) override all these settings.
    
    Parameters:
    
    resourceName - the location of the resource that should be loaded. e.g.: "weka/core/Utils.props". (The use of hardcoded forward slashes here is OK - see jdk1.1/docs/guide/misc/resources.html) This routine will also look for the file (in this case) "Utils.props" in the users home directory and the current directory.
    
    loader - the class loader to use when loading properties
    
    Returns:
    
    the Properties
    
    Throws:
    
    java.lang.Exception - if no default properties are defined, or if an error occurs reading the properties files.
  - correlation
```
public static final double correlation(double[] y1,
                                       double[] y2,
                                       int n)
```
    Returns the correlation coefficient of two double vectors.
    
    Parameters:
    
    y1 - double vector 1
    
    y2 - double vector 2
    
    n - the length of two double vectors
    
    Returns:
    
    the correlation coefficient
  - removeSubstring
```
public static java.lang.String removeSubstring(java.lang.String inString,
                                               java.lang.String substring)
```
    Removes all occurrences of a string from another string.
    
    Parameters:
    
    inString - the string to remove substrings from.
    
    substring - the substring to remove.
    
    Returns:
    
    the input string with occurrences of substring removed.
  - replaceSubstring
```
public static java.lang.String replaceSubstring(java.lang.String inString,
                                                java.lang.String subString,
                                                java.lang.String replaceString)
```
    Replaces with a new string, all occurrences of a string from another string.
    
    Parameters:
    
    inString - the string to replace substrings in.
    
    subString - the substring to replace.
    
    replaceString - the replacement substring
    
    Returns:
    
    the input string with occurrences of substring replaced.
  - padLeftAndAllowOverflow
```
public static java.lang.String padLeftAndAllowOverflow(java.lang.String inString,
                                                       int length)
```
    Pads a string to a specified length, inserting spaces on the left as required. If the string is too long, it is simply returned unchanged.
    
    Parameters:
    
    inString - the input string
    
    length - the desired length of the output string
    
    Returns:
    
    the output string
  - padRightAndAllowOverflow
```
public static java.lang.String padRightAndAllowOverflow(java.lang.String inString,
                                                        int length)
```
    Pads a string to a specified length, inserting spaces on the right as required. If the string is too long, it is simply returned unchanged.
    
    Parameters:
    
    inString - the input string
    
    length - the desired length of the output string
    
    Returns:
    
    the output string
  - padLeft
```
public static java.lang.String padLeft(java.lang.String inString,
                                       int length)
```
    Pads a string to a specified length, inserting spaces on the left as required. If the string is too long, characters are removed (from the right).
    
    Parameters:
    
    inString - the input string
    
    length - the desired length of the output string
    
    Returns:
    
    the output string
  - padRight
```
public static java.lang.String padRight(java.lang.String inString,
                                        int length)
```
    Pads a string to a specified length, inserting spaces on the right as required. If the string is too long, characters are removed (from the right).
    
    Parameters:
    
    inString - the input string
    
    length - the desired length of the output string
    
    Returns:
    
    the output string
  - doubleToString
```
public static java.lang.String doubleToString(double value,
                                              int afterDecimalPoint)
```
    Rounds a double and converts it into String.
    
    Parameters:
    
    value - the double value
    
    afterDecimalPoint - the (maximum) number of digits permitted after the decimal point
    
    Returns:
    
    the double as a formatted string
  - doubleToString
```
public static java.lang.String doubleToString(double value,
                                              int width,
                                              int afterDecimalPoint)
```
    Rounds a double and converts it into a formatted decimal-justified String. Trailing 0's are replaced with spaces.
    
    Parameters:
    
    value - the double value
    
    width - the width of the string
    
    afterDecimalPoint - the number of digits after the decimal point
    
    Returns:
    
    the double as a formatted string
  - getArrayClass
```
public static java.lang.Class<?> getArrayClass(java.lang.Class<?> c)
```
    Returns the basic class of an array class (handles multi-dimensional arrays).
    
    Parameters:
    
    c - the array to inspect
    
    Returns:
    
    the class of the innermost elements
  - getArrayDimensions
```
public static int getArrayDimensions(java.lang.Class<?> array)
```
    Returns the dimensions of the given array. Even though the parameter is of type "Object" one can hand over primitve arrays, e.g. int[3] or double[2][4].
    
    Parameters:
    
    array - the array to determine the dimensions for
    
    Returns:
    
    the dimensions of the array
  - getArrayDimensions
```
public static int getArrayDimensions(java.lang.Object array)
```
    Returns the dimensions of the given array. Even though the parameter is of type "Object" one can hand over primitve arrays, e.g. int[3] or double[2][4].
    
    Parameters:
    
    array - the array to determine the dimensions for
    
    Returns:
    
    the dimensions of the array
  - arrayToString
```
public static java.lang.String arrayToString(java.lang.Object array)
```
    Returns the given Array in a string representation. Even though the parameter is of type "Object" one can hand over primitve arrays, e.g. int[3] or double[2][4].
    
    Parameters:
    
    array - the array to return in a string representation
    
    Returns:
    
    the array as string
  - eq
```
public static boolean eq(double a,
                         double b)
```
    Tests if a is equal to b.
    
    Parameters:
    
    a - a double
    
    b - a double
  - checkForRemainingOptions
```
public static void checkForRemainingOptions(java.lang.String[] options)
                                     throws java.lang.Exception
```
    Checks if the given array contains any non-empty options.
    
    Parameters:
    
    options - an array of strings
    
    Throws:
    
    java.lang.Exception - if there are any non-empty options
  - getFlag
```
public static boolean getFlag(char flag,
                              java.lang.String[] options)
                       throws java.lang.Exception
```
    Checks if the given array contains the flag "-Char". Stops searching at the first marker "--". If the flag is found, it is replaced with the empty string.
    
    Parameters:
    
    flag - the character indicating the flag.
    
    options - the array of strings containing all the options.
    
    Returns:
    
    true if the flag was found
    
    Throws:
    
    java.lang.Exception - if an illegal option was found
  - getFlag
```
public static boolean getFlag(java.lang.String flag,
                              java.lang.String[] options)
                       throws java.lang.Exception
```
    Checks if the given array contains the flag "-String". Stops searching at the first marker "--". If the flag is found, it is replaced with the empty string.
    
    Parameters:
    
    flag - the String indicating the flag.
    
    options - the array of strings containing all the options.
    
    Returns:
    
    true if the flag was found
    
    Throws:
    
    java.lang.Exception - if an illegal option was found
  - getOption
```
public static java.lang.String getOption(char flag,
                                         java.lang.String[] options)
                                  throws java.lang.Exception
```
    Gets an option indicated by a flag "-Char" from the given array of strings. Stops searching at the first marker "--". Replaces flag and option with empty strings.
    
    Parameters:
    
    flag - the character indicating the option.
    
    options - the array of strings containing all the options.
    
    Returns:
    
    the indicated option or an empty string
    
    Throws:
    
    java.lang.Exception - if the option indicated by the flag can't be found
  - getOption
```
public static java.lang.String getOption(java.lang.String flag,
                                         java.lang.String[] options)
                                  throws java.lang.Exception
```
    Gets an option indicated by a flag "-String" from the given array of strings. Stops searching at the first marker "--". Replaces flag and option with empty strings.
    
    Parameters:
    
    flag - the String indicating the option.
    
    options - the array of strings containing all the options.
    
    Returns:
    
    the indicated option or an empty string
    
    Throws:
    
    java.lang.Exception - if the option indicated by the flag can't be found
  - getOptionPos
```
public static int getOptionPos(char flag,
                               java.lang.String[] options)
```
    Gets the index of an option or flag indicated by a flag "-Char" from the given array of strings. Stops searching at the first marker "--".
    
    Parameters:
    
    flag - the character indicating the option.
    
    options - the array of strings containing all the options.
    
    Returns:
    
    the position if found, or -1 otherwise
  - getOptionPos
```
public static int getOptionPos(java.lang.String flag,
                               java.lang.String[] options)
```
    Gets the index of an option or flag indicated by a flag "-String" from the given array of strings. Stops searching at the first marker "--".
    
    Parameters:
    
    flag - the String indicating the option.
    
    options - the array of strings containing all the options.
    
    Returns:
    
    the position if found, or -1 otherwise
  - quote
```
public static java.lang.String quote(java.lang.String string)
```
    Quotes a string if it contains special characters. The following rules are applied: A character is backquoted version of it is one of " ' % \ \n \r \t . A string is enclosed within single quotes if a character has been backquoted using the previous rule above or contains { } or is exactly equal to the strings , ? space or "" (empty string). A quoted question mark distinguishes it from the missing value which is represented as an unquoted question mark in arff files.
    
    Parameters:
    
    string - the string to be quoted
    
    Returns:
    
    the string (possibly quoted)
    
    See Also:
    
    unquote(String)
  - unquote
```
public static java.lang.String unquote(java.lang.String string)
```
    unquotes are previously quoted string (but only if necessary), i.e., it removes the single quotes around it. Inverse to quote(String).
    
    Parameters:
    
    string - the string to process
    
    Returns:
    
    the unquoted string
    
    See Also:
    
    quote(String)
  - backQuoteChars
```
public static java.lang.String backQuoteChars(java.lang.String string)
```
    Converts carriage returns and new lines in a string into \r and \n. Backquotes the following characters: ` " \ \t and %
    
    Parameters:
    
    string - the string
    
    Returns:
    
    the converted string
    
    See Also:
    
    unbackQuoteChars(String)
  - convertNewLines
```
public static java.lang.String convertNewLines(java.lang.String string)
```
    Converts carriage returns and new lines in a string into \r and \n.
    
    Parameters:
    
    string - the string
    
    Returns:
    
    the converted string
  - revertNewLines
```
public static java.lang.String revertNewLines(java.lang.String string)
```
    Reverts \r and \n in a string into carriage returns and new lines.
    
    Parameters:
    
    string - the string
    
    Returns:
    
    the converted string
  - partitionOptions
```
public static java.lang.String[] partitionOptions(java.lang.String[] options)
```
    Returns the secondary set of options (if any) contained in the supplied options array. The secondary set is defined to be any options after the first "--". These options are removed from the original options array.
    
    Parameters:
    
    options - the input array of options
    
    Returns:
    
    the array of secondary options
  - unbackQuoteChars
```
public static java.lang.String unbackQuoteChars(java.lang.String string)
```
    The inverse operation of backQuoteChars(). Converts back-quoted carriage returns and new lines in a string to the corresponding character ('\r' and '\n'). Also "un"-back-quotes the following characters: ` " \ \t and %
    
    Parameters:
    
    string - the string
    
    Returns:
    
    the converted string
    
    See Also:
    
    backQuoteChars(String)
  - replaceStrings
```
public static java.lang.String replaceStrings(java.lang.String string,
                                              java.lang.String[] charsFind,
                                              char[] charsReplace)
```
    Converts the specified strings in the given string to the specified characters.
    
    Parameters:
    
    string - the string to operate on
    
    charsFind - the strings to replace
    
    charsReplace - the characters to replace these with
    
    Returns:
    
    the converted string
  - splitOptions
```
public static java.lang.String[] splitOptions(java.lang.String quotedOptionString)
                                       throws java.lang.Exception
```
    Split up a string containing options into an array of strings, one for each option.
    
    Parameters:
    
    quotedOptionString - the string containing the options
    
    Returns:
    
    the array of options
    
    Throws:
    
    java.lang.Exception - in case of an unterminated string, unknown character or a parse error
  - splitOptions
```
public static java.lang.String[] splitOptions(java.lang.String quotedOptionString,
                                              java.lang.String[] toReplace,
                                              char[] replacements)
                                       throws java.lang.Exception
```
    Split up a string containing options into an array of strings, one for each option. If either the second or the third argument are null, the method unbackQuoteChars() is applied to each individual option string. Otherwise, the method replaceStrings() is applied to each individual option string, using the second and third argument of this method as parameters.
    
    Parameters:
    
    quotedOptionString - the string containing the options
    
    toReplace - strings to replace in each option (e.g., backquoted characters)
    
    replacements - the characters to replace the strings with
    
    Returns:
    
    the array of options
    
    Throws:
    
    java.lang.Exception - in case of an unterminated string, unknown character or a parse error
  - joinOptions
```
public static java.lang.String joinOptions(java.lang.String[] optionArray)
```
    Joins all the options in an option array into a single string, as might be used on the command line.
    
    Parameters:
    
    optionArray - the array of options
    
    Returns:
    
    the string containing all options.
  - forName
```
public static java.lang.Object forName(java.lang.Class<?> classType,
                                       java.lang.String className,
                                       java.lang.String[] options)
                                throws java.lang.Exception
```
    Creates a new instance of an object given it's class name and (optional) arguments to pass to it's setOptions method. If the object implements OptionHandler and the options parameter is non-null, the object will have it's options set. Example use:
    
    String classifierName = Utils.getOption('W', options); Classifier c = (Classifier)Utils.forName(Classifier.class, classifierName, options); setClassifier(c);
    Parameters:
    
    classType - the class that the instantiated object should be assignable to -- an exception is thrown if this is not the case
    
    className - the fully qualified class name of the object
    
    options - an array of options suitable for passing to setOptions. May be null. Any options accepted by the object will be removed from the array.
    
    Returns:
    
    the newly created object, ready for use (if it is an array, it will have size zero).
    
    Throws:
    
    java.lang.Exception - if the class name is invalid, or if the class is not assignable to the desired class type, or the options supplied are not acceptable to the object
  - getWekaJFrame
```
public static javax.swing.JFrame getWekaJFrame(java.lang.String title,
                                               java.awt.Component component)
```
    Returns a JFrame with the given title. The JFrame will be placed relative to the ancestor window of the given component (or relative to the given component itself, if it is a window), and will receive the icon image from that window if the window is a frame. The default close operation of the JFrame is set to DO_NOTHING_ON_CLOSE so code using the JFrame will need to make sure that it is disposed of properly.
    
    Parameters:
    
    title - the title of the window
    
    component - the component for which the ancestor window is found
    
    Returns:
    
    the JFrame
  - toCommandLine
```
public static java.lang.String toCommandLine(java.lang.Object obj)
```
    Generates a commandline of the given object. If the object is not implementing OptionHandler, then it will only return the classname, otherwise also the options.
    
    Parameters:
    
    obj - the object to turn into a commandline
    
    Returns:
    
    the commandline
  - info
```
public static double info(int[] counts)
```
    Computes entropy for an array of integers.
    
    Parameters:
    
    counts - array of counts
    
    Returns:
    
    - a log2 a - b log2 b - c log2 c + (a+b+c) log2 (a+b+c) when given array [a b c]
  - smOrEq
```
public static boolean smOrEq(double a,
                             double b)
```
    Tests if a is smaller or equal to b.
    
    Parameters:
    
    a - a double
    
    b - a double
  - grOrEq
```
public static boolean grOrEq(double a,
                             double b)
```
    Tests if a is greater or equal to b.
    
    Parameters:
    
    a - a double
    
    b - a double
  - sm
```
public static boolean sm(double a,
                         double b)
```
    Tests if a is smaller than b.
    
    Parameters:
    
    a - a double
    
    b - a double
  - gr
```
public static boolean gr(double a,
                         double b)
```
    Tests if a is greater than b.
    
    Parameters:
    
    a - a double
    
    b - a double
  - kthSmallestValue
```
public static int kthSmallestValue(int[] array,
                                   int k)
```
    Returns the kth-smallest value in the array.
    
    Parameters:
    
    array - the array of integers
    
    k - the value of k
    
    Returns:
    
    the kth-smallest value
  - kthSmallestValue
```
public static double kthSmallestValue(double[] array,
                                      int k)
```
    Returns the kth-smallest value in the array
    
    Parameters:
    
    array - the array of double
    
    k - the value of k
    
    Returns:
    
    the kth-smallest value
  - log2
```
public static double log2(double a)
```
    Returns the logarithm of a for base 2.
    
    Parameters:
    
    a - a double
    
    Returns:
    
    the logarithm for base 2
  - maxIndex
```
public static int maxIndex(double[] doubles)
```
    Returns index of maximum element in a given array of doubles. First maximum is returned.
    
    Parameters:
    
    doubles - the array of doubles
    
    Returns:
    
    the index of the maximum element
  - maxIndex
```
public static int maxIndex(int[] ints)
```
    Returns index of maximum element in a given array of integers. First maximum is returned.
    
    Parameters:
    
    ints - the array of integers
    
    Returns:
    
    the index of the maximum element
  - mean
```
public static double mean(double[] vector)
```
    Computes the mean for an array of doubles.
    
    Parameters:
    
    vector - the array
    
    Returns:
    
    the mean
  - minIndex
```
public static int minIndex(int[] ints)
```
    Returns index of minimum element in a given array of integers. First minimum is returned.
    
    Parameters:
    
    ints - the array of integers
    
    Returns:
    
    the index of the minimum element
  - minIndex
```
public static int minIndex(double[] doubles)
```
    Returns index of minimum element in a given array of doubles. First minimum is returned.
    
    Parameters:
    
    doubles - the array of doubles
    
    Returns:
    
    the index of the minimum element
  - normalize
```
public static void normalize(double[] doubles)
```
    Normalizes the doubles in the array by their sum.
    
    Parameters:
    
    doubles - the array of double
    
    Throws:
    
    java.lang.IllegalArgumentException - if sum is Zero or NaN
  - normalize
```
public static void normalize(double[] doubles,
                             double sum)
```
    Normalizes the doubles in the array using the given value.
    
    Parameters:
    
    doubles - the array of double
    
    sum - the value by which the doubles are to be normalized
    
    Throws:
    
    java.lang.IllegalArgumentException - if sum is zero or NaN
  - logs2probs
```
public static double[] logs2probs(double[] a)
```
    Converts an array containing the natural logarithms of probabilities stored in a vector back into probabilities. The probabilities are assumed to sum to one.
    
    Parameters:
    
    a - an array holding the natural logarithms of the probabilities
    
    Returns:
    
    the converted array
  - probToLogOdds
```
public static double probToLogOdds(double prob)
```
    Returns the log-odds for a given probabilitiy.
    
    Parameters:
    
    prob - the probabilitiy
    
    Returns:
    
    the log-odds after the probability has been mapped to [Utils.SMALL, 1-Utils.SMALL]
  - round
```
public static int round(double value)
```
    Rounds a double to the next nearest integer value. The JDK version of it doesn't work properly.
    
    Parameters:
    
    value - the double value
    
    Returns:
    
    the resulting integer value
  - probRound
```
public static int probRound(double value,
                            java.util.Random rand)
```
    Rounds a double to the next nearest integer value in a probabilistic fashion (e.g. 0.8 has a 20% chance of being rounded down to 0 and a 80% chance of being rounded up to 1). In the limit, the average of the rounded numbers generated by this procedure should converge to the original double.
    
    Parameters:
    
    value - the double value
    
    rand - the random number generator
    
    Returns:
    
    the resulting integer value
  - replaceMissingWithMAX_VALUE
```
public static void replaceMissingWithMAX_VALUE(double[] array)
```
    Replaces all "missing values" in the given array of double values with MAX_VALUE.
    
    Parameters:
    
    array - the array to be modified.
  - roundDouble
```
public static double roundDouble(double value,
                                 int afterDecimalPoint)
```
    Rounds a double to the given number of decimal places.
    
    Parameters:
    
    value - the double value
    
    afterDecimalPoint - the number of digits after the decimal point
    
    Returns:
    
    the double rounded to the given precision
  - sort
```
public static int[] sort(int[] array)
```
    Sorts a given array of integers in ascending order and returns an array of integers with the positions of the elements of the original array in the sorted array. The sort is stable. (Equal elements remain in their original order.)
    
    Parameters:
    
    array - this array is not changed by the method!
    
    Returns:
    
    an array of integers with the positions in the sorted array.
  - sort
```
public static int[] sort(double[] array)
```
    Sorts a given array of doubles in ascending order and returns an array of integers with the positions of the elements of the original array in the sorted array. NOTE THESE CHANGES: the sort is no longer stable and it doesn't use safe floating-point comparisons anymore. Occurrences of Double.NaN are treated as Double.MAX_VALUE.
    
    Parameters:
    
    array - this array is not changed by the method!
    
    Returns:
    
    an array of integers with the positions in the sorted array.
  - sortWithNoMissingValues
```
public static int[] sortWithNoMissingValues(double[] array)
```
    Sorts a given array of doubles in ascending order and returns an array of integers with the positions of the elements of the original array in the sorted array. Missing values in the given array are replaced by Double.MAX_VALUE, so the array is modified in that case!
    
    Parameters:
    
    array - the array to be sorted, which is modified if it has missing values
    
    Returns:
    
    an array of integers with the positions in the sorted array.
  - stableSort
```
public static int[] stableSort(double[] array)
```
    Sorts a given array of doubles in ascending order and returns an array of integers with the positions of the elements of the original array in the sorted array. The sort is stable (Equal elements remain in their original order.) Occurrences of Double.NaN are treated as Double.MAX_VALUE
    
    Parameters:
    
    array - this array is not changed by the method!
    
    Returns:
    
    an array of integers with the positions in the sorted array.
  - variance
```
public static double variance(double[] vector)
```
    Computes the variance for an array of doubles.
    
    Parameters:
    
    vector - the array
    
    Returns:
    
    the variance
  - sum
```
public static double sum(double[] doubles)
```
    Computes the sum of the elements of an array of doubles.
    
    Parameters:
    
    doubles - the array of double
    
    Returns:
    
    the sum of the elements
  - sum
```
public static int sum(int[] ints)
```
    Computes the sum of the elements of an array of integers.
    
    Parameters:
    
    ints - the array of integers
    
    Returns:
    
    the sum of the elements
  - xlogx
```
public static double xlogx(int c)
```
    Returns c*log2(c) for a given integer value c.
    
    Parameters:
    
    c - an integer value
    
    Returns:
    
    c*log2(c) (but is careful to return 0 if c is 0)
  - convertToRelativePath
```
public static java.io.File convertToRelativePath(java.io.File absolute)
                                          throws java.lang.Exception
```
    Converts a File's absolute path to a path relative to the user (ie start) directory. Includes an additional workaround for Cygwin, which doesn't like upper case drive letters.
    
    Parameters:
    
    absolute - the File to convert to relative path
    
    Returns:
    
    a File with a path that is relative to the user's directory
    
    Throws:
    
    java.lang.Exception - if the path cannot be constructed
  - getDontShowDialog
```
public static boolean getDontShowDialog(java.lang.String dialogName)
```
    For a named dialog, returns true if the user has opted not to view it again in the future.
    
    Parameters:
    
    dialogName - the name of the dialog to check (e.g. weka.gui.GUICHooser.HowToFindPackageManager).
    
    Returns:
    
    true if the user has opted not to view the named dialog in the future.
  - setDontShowDialog
```
public static void setDontShowDialog(java.lang.String dialogName)
                              throws java.lang.Exception
```
    Specify that the named dialog is not to be displayed in the future.
    
    Parameters:
    
    dialogName - the name of the dialog not to show again (e.g. weka.gui.GUIChooser.HowToFindPackageManager).
    
    Throws:
    
    java.lang.Exception - if the marker file that is used to indicate that a named dialog is not to be shown can't be created. This file lives in $WEKA_HOME/systemDialogs
  - getDontShowDialogResponse
```
public static java.lang.String getDontShowDialogResponse(java.lang.String dialogName)
                                                  throws java.lang.Exception
```
    For a named dialog, if the user has opted not to view it again, returns the answer the answer the user supplied when they closed the dialog. Returns null if the user did opt to view the dialog again.
    
    Parameters:
    
    dialogName - the name of the dialog to check (e.g. weka.gui.GUICHooser.HowToFindPackageManager).
    
    Returns:
    
    the answer the user supplied the last time they viewed the named dialog (if they opted not to view it again in the future) or null if the user opted to view the dialog again in the future.
    
    Throws:
    
    java.lang.Exception
  - setDontShowDialogResponse
```
public static void setDontShowDialogResponse(java.lang.String dialogName,
                                             java.lang.String response)
                                      throws java.lang.Exception
```
    Specify that the named dialog is not to be shown again in the future. Also records the answer that the user chose when closing the dialog.
    
    Parameters:
    
    dialogName - the name of the dialog to no longer display
    
    response - the user selected response when they closed the dialog
    
    Throws:
    
    java.lang.Exception - if there is a problem saving the information
  - breakUp
```
public static java.lang.String[] breakUp(java.lang.String s,
                                         int columns)
```
    Breaks up the string, if wider than "columns" characters.
    
    Parameters:
    
    s - the string to process
    
    columns - the width in columns
    
    Returns:
    
    the processed string
  - getGlobalInfo
```
public static java.lang.String getGlobalInfo(java.lang.Object object,
                                             boolean addCapabilities)
```
    Utility method for grabbing the global info help (if it exists) from an arbitrary object. Can also append capabilities information if the object is a CapabilitiesHandler.
    
    Parameters:
    
    object - the object to grab global info from
    
    addCapabilities - true if capabilities information is to be added to the result
    
    Returns:
    
    the global help info or null if global info does not exist
  - lineWrap
```
public static java.lang.String lineWrap(java.lang.String input,
                                        int maxLineWidth)
```
    Implements simple line breaking. Reformats the given string by introducing line breaks so that, ideally, no line exceeds the given number of characters. Line breaks are assumed to be indicated by newline characters. Existing line breaks are left in the input text.
    
    Parameters:
    
    input - the string to line wrap
    
    maxLineWidth - the maximum permitted number of characters in a line
    
    Returns:
    
    the processed string
  - configureRangeFromRangeStringOrAttributeNameList
```
public static Range configureRangeFromRangeStringOrAttributeNameList(Instances instanceInfo,
                                                                     java.lang.String rangeString)
                                                              throws java.lang.Exception
```
    Returns a configured Range object given a 1-based range index string (such as 1-20,35,last) or a comma-separated list of attribute names.
    
    Parameters:
    
    instanceInfo - the header of the instances to configure the range for
    
    rangeString - a string containing a range of attribute indexes, or a comma-separated list of attribute names
    
    Returns:
    
    a Range object configured to cover the supplied rangeString
    
    Throws:
    
    java.lang.Exception - if a problem occured
  - takeSample
```
public static int[] takeSample(double[] weights,
                               java.util.Random random)
```
    Takes a sample based on the given array of weights based on Walker's method. Returns an array of the same size that gives the frequency of each item in the sample. For Walker's method, see pp. 232 of "Stochastic Simulation" by B.D. Ripley (1987).
    
    Parameters:
    
    weights - the (positive) weights to be used to determine sample probabilities by normalization
    
    random - the random number generator to be used
    
    Returns:
    
    the histogram of items in the sample
  - getRevision
```
public java.lang.String getRevision()
```
    Returns the revision string.
    
    Specified by:
    
    getRevision in interface RevisionHandler
    
    Returns:
    
    the revision
  - main
```
public static void main(java.lang.String[] ops)
```
    Main method for testing this class.
    
    Parameters:
    
    ops - some dummy options

Modifier and Type	Field	Description
`static double`	`log2`	The natural logarithm of 2.
`static double`	`SMALL`	The small deviation allowed in double comparisons.

Class Utils

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

log2

SMALL

Constructor Detail

Utils

Method Detail

dateToMillis

isMissingValue

missingValue

cast

readProperties

readProperties

correlation

removeSubstring

replaceSubstring

padLeftAndAllowOverflow

padRightAndAllowOverflow

padLeft

padRight

doubleToString

doubleToString

getArrayClass

getArrayDimensions

getArrayDimensions

arrayToString

eq

checkForRemainingOptions

getFlag

getFlag

getOption

getOption

getOptionPos

getOptionPos

quote

unquote

backQuoteChars

convertNewLines

revertNewLines

partitionOptions

unbackQuoteChars

replaceStrings

splitOptions

splitOptions

joinOptions

forName

getWekaJFrame

toCommandLine

info

smOrEq

grOrEq

sm

gr

kthSmallestValue

kthSmallestValue

log2

maxIndex

maxIndex

mean

minIndex

minIndex

normalize

normalize

logs2probs

probToLogOdds

round

probRound

replaceMissingWithMAX_VALUE

roundDouble

sort

sort

sortWithNoMissingValues

stableSort

variance

sum

sum