java.util
Class Arrays
java.lang.Object
|
+--java.util.Arrays
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public class Arrays
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extends java.lang.Object
This class contains various methods for manipulating arrays (such as sorting
and searching). It also contains a static factory that allows arrays to
be viewed as lists.
The documentation for the sorting and searching methods contained
in this class includes briefs description of the implementations.
Such descriptions should be regarded as implementation notes, rather
than parts of the specification. Implementors should feel free to
substitute other algorithms, so long as the specification itself is adhered
to. (For example, the algorithm used by sort(Object[]) does not
have to be a mergesort, but it does have to be stable.)
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Since:
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1.2
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See Also:
-
Comparable, Comparator
Method Summary |
static <T> java.util.List<T> |
asList(T[] a)
Returns a fixed-size
list backed by the specified array. |
static <T> int |
binarySearch(T[]
a, T key)
Searches the
specified array for the specified object using the binary search algorithm. |
static <T> int |
binarySearch(T[]
a, T key, java.util.Comparator<T> c)
Searches the
specified array for the specified object using the binary search algorithm. |
static <T> void |
fill(T[]
a, int fromIndex, int toIndex, T val)
Assigns the
specified Object reference to each element of the specified range of the
specified array of Objects. |
static <T> void |
fill(T[] a, T
val)
Assigns the
specified Object reference to each element of the specified array of Objects. |
static <T> void |
sort(T[] a)
Sorts the specified
array of objects into ascending order, according to the natural ordering
of its elements. |
static <T> void |
sort(T[]
a, java.util.Comparator<T> c)
Sorts the specified
array of objects according to the order induced by the specified comparator. |
static int |
binarySearch(byte[]
a, byte key)
Searches the
specified array of bytes for the specified value using the binary search
algorithm. |
static int |
binarySearch(char[]
a, char key)
Searches the
specified array of chars for the specified value using the binary search
algorithm. |
static int |
binarySearch(double[]
a, double key)
Searches the
specified array of doubles for the specified value using the binary search
algorithm. |
static int |
binarySearch(float[]
a, float key)
Searches the
specified array of floats for the specified value using the binary search
algorithm. |
static int |
binarySearch(int[]
a, int key)
Searches the
specified array of ints for the specified value using the binary search
algorithm. |
static int |
binarySearch(long[]
a, long key)
Searches the
specified array of longs for the specified value using the binary search
algorithm. |
static int |
binarySearch(short[]
a, short key)
Searches the
specified array of shorts for the specified value using the binary search
algorithm. |
static boolean |
equals(boolean[]
a, boolean[] a2)
Returns true
if the two specified arrays of booleans are equal to one another. |
static boolean |
equals(byte[]
a, byte[] a2)
Returns true
if the two specified arrays of bytes are equal to one another. |
static boolean |
equals(char[]
a, char[] a2)
Returns true
if the two specified arrays of chars are equal to one another. |
static boolean |
equals(double[]
a, double[] a2)
Returns true
if the two specified arrays of doubles are equal to one another. |
static boolean |
equals(float[]
a, float[] a2)
Returns true
if the two specified arrays of floats are equal to one another. |
static boolean |
equals(int[]
a, int[] a2)
Returns true
if the two specified arrays of ints are equal to one another. |
static boolean |
equals(long[]
a, long[] a2)
Returns true
if the two specified arrays of longs are equal to one another. |
static boolean |
equals(java.lang.Object[]
a, java.lang.Object[] a2)
Returns true
if the two specified arrays of Objects are equal to one another. |
static boolean |
equals(short[]
a, short[] a2)
Returns true
if the two specified arrays of shorts are equal to one another. |
static void |
fill(boolean[]
a, boolean val)
Assigns the
specified boolean value to each element of the specified array of booleans. |
static void |
fill(boolean[]
a, int fromIndex, int toIndex, boolean val)
Assigns the
specified boolean value to each element of the specified range of the specified
array of booleans. |
static void |
fill(byte[]
a, byte val)
Assigns the
specified byte value to each element of the specified array of bytes. |
static void |
fill(byte[]
a, int fromIndex, int toIndex, byte val)
Assigns the
specified byte value to each element of the specified range of the specified
array of bytes. |
static void |
fill(char[]
a, char val)
Assigns the
specified char value to each element of the specified array of chars. |
static void |
fill(char[]
a, int fromIndex, int toIndex, char val)
Assigns the
specified char value to each element of the specified range of the specified
array of chars. |
static void |
fill(double[]
a, double val)
Assigns the
specified double value to each element of the specified array of doubles. |
static void |
fill(double[]
a, int fromIndex, int toIndex, double val)
Assigns the
specified double value to each element of the specified range of the specified
array of doubles. |
static void |
fill(float[]
a, float val)
Assigns the
specified float value to each element of the specified array of floats. |
static void |
fill(float[]
a, int fromIndex, int toIndex, float val)
Assigns the
specified float value to each element of the specified range of the specified
array of floats. |
static void |
fill(int[] a,
int val)
Assigns the
specified int value to each element of the specified array of ints. |
static void |
fill(int[]
a, int fromIndex, int toIndex, int val)
Assigns the
specified int value to each element of the specified range of the specified
array of ints. |
static void |
fill(long[]
a, int fromIndex, int toIndex, long val)
Assigns the
specified long value to each element of the specified range of the specified
array of longs. |
static void |
fill(long[]
a, long val)
Assigns the
specified long value to each element of the specified array of longs. |
static void |
fill(short[]
a, int fromIndex, int toIndex, short val)
Assigns the
specified short value to each element of the specified range of the specified
array of shorts. |
static void |
fill(short[]
a, short val)
Assigns the
specified short value to each element of the specified array of shorts. |
static void |
sort(byte[] a)
Sorts the specified
array of bytes into ascending numerical order. |
static void |
sort(byte[]
a, int fromIndex, int toIndex)
Sorts the specified
range of the specified array of bytes into ascending numerical order. |
static void |
sort(char[] a)
Sorts the specified
array of chars into ascending numerical order. |
static void |
sort(char[]
a, int fromIndex, int toIndex)
Sorts the specified
range of the specified array of chars into ascending numerical order. |
static void |
sort(double[] a)
Sorts the specified
array of doubles into ascending numerical order. |
static void |
sort(double[]
a, int fromIndex, int toIndex)
Sorts the specified
range of the specified array of doubles into ascending numerical order. |
static void |
sort(float[] a)
Sorts the specified
array of floats into ascending numerical order. |
static void |
sort(float[]
a, int fromIndex, int toIndex)
Sorts the specified
range of the specified array of floats into ascending numerical order. |
static void |
sort(int[] a)
Sorts the specified
array of ints into ascending numerical order. |
static void |
sort(int[]
a, int fromIndex, int toIndex)
Sorts the specified
range of the specified array of ints into ascending numerical order. |
static void |
sort(long[] a)
Sorts the specified
array of longs into ascending numerical order. |
static void |
sort(long[]
a, int fromIndex, int toIndex)
Sorts the specified
range of the specified array of longs into ascending numerical order. |
static void |
sort(java.lang.Object[]
a, int fromIndex, int toIndex)
Sorts the specified
range of the specified array of objects into ascending order, according
to the natural ordering of its elements. |
static void |
sort(java.lang.Object[]
a, int fromIndex, int toIndex, java.util.Comparator c)
Sorts the specified
range of the specified array of objects according to the order induced
by the specified comparator. |
static void |
sort(short[] a)
Sorts the specified
array of shorts into ascending numerical order. |
static void |
sort(short[]
a, int fromIndex, int toIndex)
Sorts the specified
range of the specified array of shorts into ascending numerical order. |
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll,
toString, wait, wait, wait |
sort
public static void sort(long[] a)
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Sorts the specified array of longs into ascending numerical order. The
sorting algorithm is a tuned quicksort, adapted from Jon L. Bentley and
M. Douglas McIlroy's "Engineering a Sort Function", Software-Practice and
Experience, Vol. 23(11) P. 1249-1265 (November 1993). This algorithm offers
n*log(n) performance on many data sets that cause other quicksorts to degrade
to quadratic performance.
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Parameters:
-
a - the array to be sorted.
sort
public static void sort(long[] a,
int fromIndex,
int toIndex)
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Sorts the specified range of the specified array of longs into ascending
numerical order. The range to be sorted extends from index fromIndex,
inclusive, to index toIndex, exclusive. (If fromIndex==toIndex,
the range to be sorted is empty.)
The sorting algorithm is a tuned quicksort, adapted from Jon L.
Bentley and M. Douglas McIlroy's "Engineering a Sort Function", Software-Practice
and Experience, Vol. 23(11) P. 1249-1265 (November 1993). This algorithm
offers n*log(n) performance on many data sets that cause other quicksorts
to degrade to quadratic performance.
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Parameters:
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a - the array to be sorted.
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fromIndex - the index of the first element (inclusive) to be sorted.
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toIndex - the index of the last element (exclusive) to be sorted.
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Throws:
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java.lang.IllegalArgumentException - if fromIndex > toIndex
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java.lang.ArrayIndexOutOfBoundsException - if fromIndex <
0 or toIndex > a.length
sort
public static void sort(int[] a)
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Sorts the specified array of ints into ascending numerical order. The sorting
algorithm is a tuned quicksort, adapted from Jon L. Bentley and M. Douglas
McIlroy's "Engineering a Sort Function", Software-Practice and Experience,
Vol. 23(11) P. 1249-1265 (November 1993). This algorithm offers n*log(n)
performance on many data sets that cause other quicksorts to degrade to
quadratic performance.
-
Parameters:
-
a - the array to be sorted.
sort
public static void sort(int[] a,
int fromIndex,
int toIndex)
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Sorts the specified range of the specified array of ints into ascending
numerical order. The range to be sorted extends from index fromIndex,
inclusive, to index toIndex, exclusive. (If fromIndex==toIndex,
the range to be sorted is empty.)
The sorting algorithm is a tuned quicksort, adapted from Jon
L. Bentley and M. Douglas McIlroy's "Engineering a Sort Function", Software-Practice
and Experience, Vol. 23(11) P. 1249-1265 (November 1993). This algorithm
offers n*log(n) performance on many data sets that cause other quicksorts
to degrade to quadratic performance.
-
Parameters:
-
a - the array to be sorted.
-
fromIndex - the index of the first element (inclusive) to be sorted.
-
toIndex - the index of the last element (exclusive) to be sorted.
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Throws:
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java.lang.IllegalArgumentException - if fromIndex > toIndex
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java.lang.ArrayIndexOutOfBoundsException - if fromIndex <
0 or toIndex > a.length
sort
public static void sort(short[] a)
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Sorts the specified array of shorts into ascending numerical order. The
sorting algorithm is a tuned quicksort, adapted from Jon L. Bentley and
M. Douglas McIlroy's "Engineering a Sort Function", Software-Practice and
Experience, Vol. 23(11) P. 1249-1265 (November 1993). This algorithm offers
n*log(n) performance on many data sets that cause other quicksorts to degrade
to quadratic performance.
-
Parameters:
-
a - the array to be sorted.
sort
public static void sort(short[] a,
int fromIndex,
int toIndex)
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Sorts the specified range of the specified array of shorts into ascending
numerical order. The range to be sorted extends from index fromIndex,
inclusive, to index toIndex, exclusive. (If fromIndex==toIndex,
the range to be sorted is empty.)
The sorting algorithm is a tuned quicksort, adapted from Jon
L. Bentley and M. Douglas McIlroy's "Engineering a Sort Function", Software-Practice
and Experience, Vol. 23(11) P. 1249-1265 (November 1993). This algorithm
offers n*log(n) performance on many data sets that cause other quicksorts
to degrade to quadratic performance.
-
Parameters:
-
a - the array to be sorted.
-
fromIndex - the index of the first element (inclusive) to be sorted.
-
toIndex - the index of the last element (exclusive) to be sorted.
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Throws:
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java.lang.IllegalArgumentException - if fromIndex > toIndex
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java.lang.ArrayIndexOutOfBoundsException - if fromIndex <
0 or toIndex > a.length
sort
public static void sort(char[] a)
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Sorts the specified array of chars into ascending numerical order. The
sorting algorithm is a tuned quicksort, adapted from Jon L. Bentley and
M. Douglas McIlroy's "Engineering a Sort Function", Software-Practice and
Experience, Vol. 23(11) P. 1249-1265 (November 1993). This algorithm offers
n*log(n) performance on many data sets that cause other quicksorts to degrade
to quadratic performance.
-
Parameters:
-
a - the array to be sorted.
sort
public static void sort(char[] a,
int fromIndex,
int toIndex)
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Sorts the specified range of the specified array of chars into ascending
numerical order. The range to be sorted extends from index fromIndex,
inclusive, to index toIndex, exclusive. (If fromIndex==toIndex,
the range to be sorted is empty.)
The sorting algorithm is a tuned quicksort, adapted from Jon
L. Bentley and M. Douglas McIlroy's "Engineering a Sort Function", Software-Practice
and Experience, Vol. 23(11) P. 1249-1265 (November 1993). This algorithm
offers n*log(n) performance on many data sets that cause other quicksorts
to degrade to quadratic performance.
-
Parameters:
-
a - the array to be sorted.
-
fromIndex - the index of the first element (inclusive) to be sorted.
-
toIndex - the index of the last element (exclusive) to be sorted.
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Throws:
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java.lang.IllegalArgumentException - if fromIndex > toIndex
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java.lang.ArrayIndexOutOfBoundsException - if fromIndex <
0 or toIndex > a.length
sort
public static void sort(byte[] a)
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Sorts the specified array of bytes into ascending numerical order. The
sorting algorithm is a tuned quicksort, adapted from Jon L. Bentley and
M. Douglas McIlroy's "Engineering a Sort Function", Software-Practice and
Experience, Vol. 23(11) P. 1249-1265 (November 1993). This algorithm offers
n*log(n) performance on many data sets that cause other quicksorts to degrade
to quadratic performance.
-
Parameters:
-
a - the array to be sorted.
sort
public static void sort(byte[] a,
int fromIndex,
int toIndex)
-
Sorts the specified range of the specified array of bytes into ascending
numerical order. The range to be sorted extends from index fromIndex,
inclusive, to index toIndex, exclusive. (If fromIndex==toIndex,
the range to be sorted is empty.)
The sorting algorithm is a tuned quicksort, adapted from Jon
L. Bentley and M. Douglas McIlroy's "Engineering a Sort Function", Software-Practice
and Experience, Vol. 23(11) P. 1249-1265 (November 1993). This algorithm
offers n*log(n) performance on many data sets that cause other quicksorts
to degrade to quadratic performance.
-
Parameters:
-
a - the array to be sorted.
-
fromIndex - the index of the first element (inclusive) to be sorted.
-
toIndex - the index of the last element (exclusive) to be sorted.
-
Throws:
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java.lang.IllegalArgumentException - if fromIndex > toIndex
-
java.lang.ArrayIndexOutOfBoundsException - if fromIndex <
0 or toIndex > a.length
sort
public static void sort(double[] a)
-
Sorts the specified array of doubles into ascending numerical order. The
sorting algorithm is a tuned quicksort, adapted from Jon L. Bentley and
M. Douglas McIlroy's "Engineering a Sort Function", Software-Practice and
Experience, Vol. 23(11) P. 1249-1265 (November 1993). This algorithm offers
n*log(n) performance on many data sets that cause other quicksorts to degrade
to quadratic performance.
-
Parameters:
-
a - the array to be sorted.
sort
public static void sort(double[] a,
int fromIndex,
int toIndex)
-
Sorts the specified range of the specified array of doubles into ascending
numerical order. The range to be sorted extends from index fromIndex,
inclusive, to index toIndex, exclusive. (If fromIndex==toIndex,
the range to be sorted is empty.)
The sorting algorithm is a tuned quicksort, adapted from Jon
L. Bentley and M. Douglas McIlroy's "Engineering a Sort Function", Software-Practice
and Experience, Vol. 23(11) P. 1249-1265 (November 1993). This algorithm
offers n*log(n) performance on many data sets that cause other quicksorts
to degrade to quadratic performance.
-
Parameters:
-
a - the array to be sorted.
-
fromIndex - the index of the first element (inclusive) to be sorted.
-
toIndex - the index of the last element (exclusive) to be sorted.
-
Throws:
-
java.lang.IllegalArgumentException - if fromIndex > toIndex
-
java.lang.ArrayIndexOutOfBoundsException - if fromIndex <
0 or toIndex > a.length
sort
public static void sort(float[] a)
-
Sorts the specified array of floats into ascending numerical order. The
sorting algorithm is a tuned quicksort, adapted from Jon L. Bentley and
M. Douglas McIlroy's "Engineering a Sort Function", Software-Practice and
Experience, Vol. 23(11) P. 1249-1265 (November 1993). This algorithm offers
n*log(n) performance on many data sets that cause other quicksorts to degrade
to quadratic performance.
-
Parameters:
-
a - the array to be sorted.
sort
public static void sort(float[] a,
int fromIndex,
int toIndex)
-
Sorts the specified range of the specified array of floats into ascending
numerical order. The range to be sorted extends from index fromIndex,
inclusive, to index toIndex, exclusive. (If fromIndex==toIndex,
the range to be sorted is empty.)
The sorting algorithm is a tuned quicksort, adapted from Jon
L. Bentley and M. Douglas McIlroy's "Engineering a Sort Function", Software-Practice
and Experience, Vol. 23(11) P. 1249-1265 (November 1993). This algorithm
offers n*log(n) performance on many data sets that cause other quicksorts
to degrade to quadratic performance.
-
Parameters:
-
a - the array to be sorted.
-
fromIndex - the index of the first element (inclusive) to be sorted.
-
toIndex - the index of the last element (exclusive) to be sorted.
-
Throws:
-
java.lang.IllegalArgumentException - if fromIndex > toIndex
-
java.lang.ArrayIndexOutOfBoundsException - if fromIndex <
0 or toIndex > a.length
sort
public static <T> void sort(T[] a)
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Sorts the specified array of objects into ascending order, according to
the natural ordering of its elements. All elements in the array
must implement the Comparable interface. Furthermore, all elements
in the array must be mutually comparable (that is, e1.compareTo(e2)
must not throw a ClassCastException for any elements e1
and e2 in the array).
This sort is guaranteed to be stable: equal elements
will not be reordered as a result of the sort.
The sorting algorithm is a modified mergesort (in which the merge
is omitted if the highest element in the low sublist is less than the lowest
element in the high sublist). This algorithm offers guaranteed n*log(n)
performance, and can approach linear performance on nearly sorted lists.
-
Parameters:
-
a - the array to be sorted.
-
Throws:
-
java.lang.ClassCastException - if the array contains elements
that are not mutually comparable (for example, strings and integers).
-
See Also:
-
Comparable
sort
public static void sort(java.lang.Object[] a,
int fromIndex,
int toIndex)
-
Sorts the specified range of the specified array of objects into ascending
order, according to the natural ordering of its elements. The range
to be sorted extends from index fromIndex, inclusive, to index
toIndex, exclusive. (If fromIndex==toIndex, the range
to be sorted is empty.) All elements in this range must implement the Comparable
interface. Furthermore, all elements in this range must be mutually
comparable (that is, e1.compareTo(e2) must not throw a ClassCastException
for any elements e1 and e2 in the array).
This sort is guaranteed to be stable: equal elements
will not be reordered as a result of the sort.
The sorting algorithm is a modified mergesort (in which the merge
is omitted if the highest element in the low sublist is less than the lowest
element in the high sublist). This algorithm offers guaranteed n*log(n)
performance, and can approach linear performance on nearly sorted lists.
-
Parameters:
-
a - the array to be sorted.
-
fromIndex - the index of the first element (inclusive) to be sorted.
-
toIndex - the index of the last element (exclusive) to be sorted.
-
Throws:
-
java.lang.IllegalArgumentException - if fromIndex > toIndex
-
java.lang.ArrayIndexOutOfBoundsException - if fromIndex <
0 or toIndex > a.length
-
java.lang.ClassCastException - if the array contains elements
that are not mutually comparable (for example, strings and integers).
-
See Also:
-
Comparable
sort
public static <T> void sort(T[] a,
java.util.Comparator<T> c)
-
Sorts the specified array of objects according to the order induced by
the specified comparator. All elements in the array must be mutually
comparable by the specified comparator (that is, c.compare(e1,
e2) must not throw a ClassCastException for any elements
e1 and e2 in the array).
This sort is guaranteed to be stable: equal elements
will not be reordered as a result of the sort.
The sorting algorithm is a modified mergesort (in which the merge
is omitted if the highest element in the low sublist is less than the lowest
element in the high sublist). This algorithm offers guaranteed n*log(n)
performance, and can approach linear performance on nearly sorted lists.
-
Parameters:
-
a - the array to be sorted.
-
c - the comparator to determine the order of the array. A null
value indicates that the elements' natural ordering should be used.
-
Throws:
-
java.lang.ClassCastException - if the array contains elements
that are not mutually comparable using the specified comparator.
-
See Also:
-
Comparator
sort
public static void sort(java.lang.Object[] a,
int fromIndex,
int toIndex,
java.util.Comparator c)
-
Sorts the specified range of the specified array of objects according to
the order induced by the specified comparator. The range to be sorted extends
from index fromIndex, inclusive, to index toIndex, exclusive.
(If fromIndex==toIndex, the range to be sorted is empty.) All
elements in the range must be mutually comparable by the specified
comparator (that is, c.compare(e1, e2) must not throw a ClassCastException
for any elements e1 and e2 in the range).
This sort is guaranteed to be stable: equal elements
will not be reordered as a result of the sort.
The sorting algorithm is a modified mergesort (in which the merge
is omitted if the highest element in the low sublist is less than the lowest
element in the high sublist). This algorithm offers guaranteed n*log(n)
performance, and can approach linear performance on nearly sorted lists.
-
Parameters:
-
a - the array to be sorted.
-
fromIndex - the index of the first element (inclusive) to be sorted.
-
toIndex - the index of the last element (exclusive) to be sorted.
-
c - the comparator to determine the order of the array. A null
value indicates that the elements' natural ordering should be used.
-
Throws:
-
java.lang.ClassCastException - if the array contains elements
that are not mutually comparable using the specified comparator.
-
java.lang.IllegalArgumentException - if fromIndex > toIndex
-
java.lang.ArrayIndexOutOfBoundsException - if fromIndex <
0 or toIndex > a.length
-
See Also:
-
Comparator
binarySearch
public static int binarySearch(long[] a,
long key)
-
Searches the specified array of longs for the specified value using the
binary search algorithm. The array must be sorted (as by the sort
method, above) prior to making this call. If it is not sorted, the results
are undefined. If the array contains multiple elements with the specified
value, there is no guarantee which one will be found.
-
Parameters:
-
a - the array to be searched.
-
key - the value to be searched for.
-
Returns:
-
index of the search key, if it is contained in the list; otherwise, (-(insertion
point) - 1). The insertion point is defined as the point
at which the key would be inserted into the list: the index of the first
element greater than the key, or list.size(), if all elements
in the list are less than the specified key. Note that this guarantees
that the return value will be >= 0 if and only if the key is found.
-
See Also:
-
sort(long[])
binarySearch
public static int binarySearch(int[] a,
int key)
-
Searches the specified array of ints for the specified value using the
binary search algorithm. The array must be sorted (as by the sort
method, above) prior to making this call. If it is not sorted, the results
are undefined. If the array contains multiple elements with the specified
value, there is no guarantee which one will be found.
-
Parameters:
-
a - the array to be searched.
-
key - the value to be searched for.
-
Returns:
-
index of the search key, if it is contained in the list; otherwise, (-(insertion
point) - 1). The insertion point is defined as the point
at which the key would be inserted into the list: the index of the first
element greater than the key, or list.size(), if all elements
in the list are less than the specified key. Note that this guarantees
that the return value will be >= 0 if and only if the key is found.
-
See Also:
-
sort(int[])
binarySearch
public static int binarySearch(short[] a,
short key)
-
Searches the specified array of shorts for the specified value using the
binary search algorithm. The array must be sorted (as by the sort
method, above) prior to making this call. If it is not sorted, the results
are undefined. If the array contains multiple elements with the specified
value, there is no guarantee which one will be found.
-
Parameters:
-
a - the array to be searched.
-
key - the value to be searched for.
-
Returns:
-
index of the search key, if it is contained in the list; otherwise, (-(insertion
point) - 1). The insertion point is defined as the point
at which the key would be inserted into the list: the index of the first
element greater than the key, or list.size(), if all elements
in the list are less than the specified key. Note that this guarantees
that the return value will be >= 0 if and only if the key is found.
-
See Also:
-
sort(short[])
binarySearch
public static int binarySearch(char[] a,
char key)
-
Searches the specified array of chars for the specified value using the
binary search algorithm. The array must be sorted (as by the sort
method, above) prior to making this call. If it is not sorted, the results
are undefined. If the array contains multiple elements with the specified
value, there is no guarantee which one will be found.
-
Parameters:
-
a - the array to be searched.
-
key - the value to be searched for.
-
Returns:
-
index of the search key, if it is contained in the list; otherwise, (-(insertion
point) - 1). The insertion point is defined as the point
at which the key would be inserted into the list: the index of the first
element greater than the key, or list.size(), if all elements
in the list are less than the specified key. Note that this guarantees
that the return value will be >= 0 if and only if the key is found.
-
See Also:
-
sort(char[])
binarySearch
public static int binarySearch(byte[] a,
byte key)
-
Searches the specified array of bytes for the specified value using the
binary search algorithm. The array must be sorted (as by the sort
method, above) prior to making this call. If it is not sorted, the results
are undefined. If the array contains multiple elements with the specified
value, there is no guarantee which one will be found.
-
Parameters:
-
a - the array to be searched.
-
key - the value to be searched for.
-
Returns:
-
index of the search key, if it is contained in the list; otherwise, (-(insertion
point) - 1). The insertion point is defined as the point
at which the key would be inserted into the list: the index of the first
element greater than the key, or list.size(), if all elements
in the list are less than the specified key. Note that this guarantees
that the return value will be >= 0 if and only if the key is found.
-
See Also:
-
sort(byte[])
binarySearch
public static int binarySearch(double[] a,
double key)
-
Searches the specified array of doubles for the specified value using the
binary search algorithm. The array must be sorted (as by the sort
method, above) prior to making this call. If it is not sorted, the results
are undefined. If the array contains multiple elements with the specified
value, there is no guarantee which one will be found.
-
Parameters:
-
a - the array to be searched.
-
key - the value to be searched for.
-
Returns:
-
index of the search key, if it is contained in the list; otherwise, (-(insertion
point) - 1). The insertion point is defined as the point
at which the key would be inserted into the list: the index of the first
element greater than the key, or list.size(), if all elements
in the list are less than the specified key. Note that this guarantees
that the return value will be >= 0 if and only if the key is found.
-
See Also:
-
sort(double[])
binarySearch
public static int binarySearch(float[] a,
float key)
-
Searches the specified array of floats for the specified value using the
binary search algorithm. The array must be sorted (as by the sort
method, above) prior to making this call. If it is not sorted, the results
are undefined. If the array contains multiple elements with the specified
value, there is no guarantee which one will be found.
-
Parameters:
-
a - the array to be searched.
-
key - the value to be searched for.
-
Returns:
-
index of the search key, if it is contained in the list; otherwise, (-(insertion
point) - 1). The insertion point is defined as the point
at which the key would be inserted into the list: the index of the first
element greater than the key, or list.size(), if all elements
in the list are less than the specified key. Note that this guarantees
that the return value will be >= 0 if and only if the key is found.
-
See Also:
-
sort(float[])
binarySearch
public static <T> int binarySearch(T[] a,
T key)
-
Searches the specified array for the specified object using the binary
search algorithm. The array must be sorted into ascending order according
to the natural ordering of its elements (as by Sort(Object[]),
above) prior to making this call. If it is not sorted, the results are
undefined. (If the array contains elements that are not mutually comparable
(for example,strings and integers), it cannot be sorted according
to the natural order of its elements, hence results are undefined.) If
the array contains multiple elements equal to the specified object, there
is no guarantee which one will be found.
-
Parameters:
-
a - the array to be searched.
-
key - the value to be searched for.
-
Returns:
-
index of the search key, if it is contained in the list; otherwise, (-(insertion
point) - 1). The insertion point is defined as the point
at which the key would be inserted into the list: the index of the first
element greater than the key, or list.size(), if all elements
in the list are less than the specified key. Note that this guarantees
that the return value will be >= 0 if and only if the key is found.
-
Throws:
-
java.lang.ClassCastException - if the search key in not comparable
to the elements of the array.
-
See Also:
-
Comparable, #sort(Object[])
binarySearch
public static <T> int binarySearch(T[] a,
T key,
java.util.Comparator<T> c)
-
Searches the specified array for the specified object using the binary
search algorithm. The array must be sorted into ascending order according
to the specified comparator (as by the Sort(Object[], Comparator)
method, above), prior to making this call. If it is not sorted, the results
are undefined. If the array contains multiple elements equal to the specified
object, there is no guarantee which one will be found.
-
Parameters:
-
a - the array to be searched.
-
key - the value to be searched for.
-
c - the comparator by which the array is ordered. A null
value indicates that the elements' natural ordering should be used.
-
Returns:
-
index of the search key, if it is contained in the list; otherwise, (-(insertion
point) - 1). The insertion point is defined as the point
at which the key would be inserted into the list: the index of the first
element greater than the key, or list.size(), if all elements
in the list are less than the specified key. Note that this guarantees
that the return value will be >= 0 if and only if the key is found.
-
Throws:
-
java.lang.ClassCastException - if the array contains elements
that are not mutually comparable using the specified comparator,
or the search key in not mutually comparable with the elements of the array
using this comparator.
-
See Also:
-
Comparable, #sort(Object[], Comparator)
equals
public static boolean equals(long[] a,
long[] a2)
-
Returns true if the two specified arrays of longs are equal
to one another. Two arrays are considered equal if both arrays contain
the same number of elements, and all corresponding pairs of elements in
the two arrays are equal. In other words, two arrays are equal if they
contain the same elements in the same order. Also, two array references
are considered equal if both are null.
-
Parameters:
-
a - one array to be tested for equality.
-
a2 - the other array to be tested for equality.
-
Returns:
-
true if the two arrays are equal.
equals
public static boolean equals(int[] a,
int[] a2)
-
Returns true if the two specified arrays of ints are equal
to one another. Two arrays are considered equal if both arrays contain
the same number of elements, and all corresponding pairs of elements in
the two arrays are equal. In other words, two arrays are equal if they
contain the same elements in the same order. Also, two array references
are considered equal if both are null.
-
Parameters:
-
a - one array to be tested for equality.
-
a2 - the other array to be tested for equality.
-
Returns:
-
true if the two arrays are equal.
equals
public static boolean equals(short[] a,
short[] a2)
-
Returns true if the two specified arrays of shorts are equal
to one another. Two arrays are considered equal if both arrays contain
the same number of elements, and all corresponding pairs of elements in
the two arrays are equal. In other words, two arrays are equal if they
contain the same elements in the same order. Also, two array references
are considered equal if both are null.
-
Parameters:
-
a - one array to be tested for equality.
-
a2 - the other array to be tested for equality.
-
Returns:
-
true if the two arrays are equal.
equals
public static boolean equals(char[] a,
char[] a2)
-
Returns true if the two specified arrays of chars are equal
to one another. Two arrays are considered equal if both arrays contain
the same number of elements, and all corresponding pairs of elements in
the two arrays are equal. In other words, two arrays are equal if they
contain the same elements in the same order. Also, two array references
are considered equal if both are null.
-
Parameters:
-
a - one array to be tested for equality.
-
a2 - the other array to be tested for equality.
-
Returns:
-
true if the two arrays are equal.
equals
public static boolean equals(byte[] a,
byte[] a2)
-
Returns true if the two specified arrays of bytes are equal
to one another. Two arrays are considered equal if both arrays contain
the same number of elements, and all corresponding pairs of elements in
the two arrays are equal. In other words, two arrays are equal if they
contain the same elements in the same order. Also, two array references
are considered equal if both are null.
-
Parameters:
-
a - one array to be tested for equality.
-
a2 - the other array to be tested for equality.
-
Returns:
-
true if the two arrays are equal.
equals
public static boolean equals(boolean[] a,
boolean[] a2)
-
Returns true if the two specified arrays of booleans are equal
to one another. Two arrays are considered equal if both arrays contain
the same number of elements, and all corresponding pairs of elements in
the two arrays are equal. In other words, two arrays are equal if they
contain the same elements in the same order. Also, two array references
are considered equal if both are null.
-
Parameters:
-
a - one array to be tested for equality.
-
a2 - the other array to be tested for equality.
-
Returns:
-
true if the two arrays are equal.
equals
public static boolean equals(double[] a,
double[] a2)
-
Returns true if the two specified arrays of doubles are equal
to one another. Two arrays are considered equal if both arrays contain
the same number of elements, and all corresponding pairs of elements in
the two arrays are equal. In other words, two arrays are equal if they
contain the same elements in the same order. Also, two array references
are considered equal if both are null.
Two doubles d1 and d2 are considered equal
if:
new Double(d1).equals(new Double(d2))
(Unlike the == operator, this method considers NaN equals
to itself, and 0.0d unequal to -0.0d.)
-
Parameters:
-
a - one array to be tested for equality.
-
a2 - the other array to be tested for equality.
-
Returns:
-
true if the two arrays are equal.
-
See Also:
-
Double.equals(Object)
equals
public static boolean equals(float[] a,
float[] a2)
-
Returns true if the two specified arrays of floats are equal
to one another. Two arrays are considered equal if both arrays contain
the same number of elements, and all corresponding pairs of elements in
the two arrays are equal. In other words, two arrays are equal if they
contain the same elements in the same order. Also, two array references
are considered equal if both are null.
Two floats f1 and f2 are considered equal
if:
new Float(f1).equals(new Float(f2))
(Unlike the == operator, this method considers NaN equals
to itself, and 0.0f unequal to -0.0f.)
-
Parameters:
-
a - one array to be tested for equality.
-
a2 - the other array to be tested for equality.
-
Returns:
-
true if the two arrays are equal.
-
See Also:
-
Float.equals(Object)
equals
public static boolean equals(java.lang.Object[] a,
java.lang.Object[] a2)
-
Returns true if the two specified arrays of Objects are equal
to one another. The two arrays are considered equal if both arrays contain
the same number of elements, and all corresponding pairs of elements in
the two arrays are equal. Two objects e1 and e2 are considered
equal if (e1==null ? e2==null : e1.equals(e2)). In other
words, the two arrays are equal if they contain the same elements in the
same order. Also, two array references are considered equal if both are
null.
-
Parameters:
-
a - one array to be tested for equality.
-
a2 - the other array to be tested for equality.
-
Returns:
-
true if the two arrays are equal.
fill
public static void fill(long[] a,
long val)
-
Assigns the specified long value to each element of the specified array
of longs.
-
Parameters:
-
a - the array to be filled.
-
val - the value to be stored in all elements of the array.
fill
public static void fill(long[] a,
int fromIndex,
int toIndex,
long val)
-
Assigns the specified long value to each element of the specified range
of the specified array of longs. The range to be filled extends from index
fromIndex, inclusive, to index toIndex, exclusive. (If
fromIndex==toIndex, the range to be filled is empty.)
-
Parameters:
-
a - the array to be filled.
-
fromIndex - the index of the first element (inclusive) to be filled
with the specified value.
-
toIndex - the index of the last element (exclusive) to be filled
with the specified value.
-
val - the value to be stored in all elements of the array.
-
Throws:
-
java.lang.IllegalArgumentException - if fromIndex > toIndex
-
java.lang.ArrayIndexOutOfBoundsException - if fromIndex <
0 or toIndex > a.length
fill
public static void fill(int[] a,
int val)
-
Assigns the specified int value to each element of the specified array
of ints.
-
Parameters:
-
a - the array to be filled.
-
val - the value to be stored in all elements of the array.
fill
public static void fill(int[] a,
int fromIndex,
int toIndex,
int val)
-
Assigns the specified int value to each element of the specified range
of the specified array of ints. The range to be filled extends from index
fromIndex, inclusive, to index toIndex, exclusive. (If
fromIndex==toIndex, the range to be filled is empty.)
-
Parameters:
-
a - the array to be filled.
-
fromIndex - the index of the first element (inclusive) to be filled
with the specified value.
-
toIndex - the index of the last element (exclusive) to be filled
with the specified value.
-
val - the value to be stored in all elements of the array.
-
Throws:
-
java.lang.IllegalArgumentException - if fromIndex > toIndex
-
java.lang.ArrayIndexOutOfBoundsException - if fromIndex <
0 or toIndex > a.length
fill
public static void fill(short[] a,
short val)
-
Assigns the specified short value to each element of the specified array
of shorts.
-
Parameters:
-
a - the array to be filled.
-
val - the value to be stored in all elements of the array.
fill
public static void fill(short[] a,
int fromIndex,
int toIndex,
short val)
-
Assigns the specified short value to each element of the specified range
of the specified array of shorts. The range to be filled extends from index
fromIndex, inclusive, to index toIndex, exclusive. (If
fromIndex==toIndex, the range to be filled is empty.)
-
Parameters:
-
a - the array to be filled.
-
fromIndex - the index of the first element (inclusive) to be filled
with the specified value.
-
toIndex - the index of the last element (exclusive) to be filled
with the specified value.
-
val - the value to be stored in all elements of the array.
-
Throws:
-
java.lang.IllegalArgumentException - if fromIndex > toIndex
-
java.lang.ArrayIndexOutOfBoundsException - if fromIndex <
0 or toIndex > a.length
fill
public static void fill(char[] a,
char val)
-
Assigns the specified char value to each element of the specified array
of chars.
-
Parameters:
-
a - the array to be filled.
-
val - the value to be stored in all elements of the array.
fill
public static void fill(char[] a,
int fromIndex,
int toIndex,
char val)
-
Assigns the specified char value to each element of the specified range
of the specified array of chars. The range to be filled extends from index
fromIndex, inclusive, to index toIndex, exclusive. (If
fromIndex==toIndex, the range to be filled is empty.)
-
Parameters:
-
a - the array to be filled.
-
fromIndex - the index of the first element (inclusive) to be filled
with the specified value.
-
toIndex - the index of the last element (exclusive) to be filled
with the specified value.
-
val - the value to be stored in all elements of the array.
-
Throws:
-
java.lang.IllegalArgumentException - if fromIndex > toIndex
-
java.lang.ArrayIndexOutOfBoundsException - if fromIndex <
0 or toIndex > a.length
fill
public static void fill(byte[] a,
byte val)
-
Assigns the specified byte value to each element of the specified array
of bytes.
-
Parameters:
-
a - the array to be filled.
-
val - the value to be stored in all elements of the array.
fill
public static void fill(byte[] a,
int fromIndex,
int toIndex,
byte val)
-
Assigns the specified byte value to each element of the specified range
of the specified array of bytes. The range to be filled extends from index
fromIndex, inclusive, to index toIndex, exclusive. (If
fromIndex==toIndex, the range to be filled is empty.)
-
Parameters:
-
a - the array to be filled.
-
fromIndex - the index of the first element (inclusive) to be filled
with the specified value.
-
toIndex - the index of the last element (exclusive) to be filled
with the specified value.
-
val - the value to be stored in all elements of the array.
-
Throws:
-
java.lang.IllegalArgumentException - if fromIndex > toIndex
-
java.lang.ArrayIndexOutOfBoundsException - if fromIndex <
0 or toIndex > a.length
fill
public static void fill(boolean[] a,
boolean val)
-
Assigns the specified boolean value to each element of the specified array
of booleans.
-
Parameters:
-
a - the array to be filled.
-
val - the value to be stored in all elements of the array.
fill
public static void fill(boolean[] a,
int fromIndex,
int toIndex,
boolean val)
-
Assigns the specified boolean value to each element of the specified range
of the specified array of booleans. The range to be filled extends from
index fromIndex, inclusive, to index toIndex, exclusive.
(If fromIndex==toIndex, the range to be filled is empty.)
-
Parameters:
-
a - the array to be filled.
-
fromIndex - the index of the first element (inclusive) to be filled
with the specified value.
-
toIndex - the index of the last element (exclusive) to be filled
with the specified value.
-
val - the value to be stored in all elements of the array.
-
Throws:
-
java.lang.IllegalArgumentException - if fromIndex > toIndex
-
java.lang.ArrayIndexOutOfBoundsException - if fromIndex <
0 or toIndex > a.length
fill
public static void fill(double[] a,
double val)
-
Assigns the specified double value to each element of the specified array
of doubles.
-
Parameters:
-
a - the array to be filled.
-
val - the value to be stored in all elements of the array.
fill
public static void fill(double[] a,
int fromIndex,
int toIndex,
double val)
-
Assigns the specified double value to each element of the specified range
of the specified array of doubles. The range to be filled extends from
index fromIndex, inclusive, to index toIndex, exclusive.
(If fromIndex==toIndex, the range to be filled is empty.)
-
Parameters:
-
a - the array to be filled.
-
fromIndex - the index of the first element (inclusive) to be filled
with the specified value.
-
toIndex - the index of the last element (exclusive) to be filled
with the specified value.
-
val - the value to be stored in all elements of the array.
-
Throws:
-
java.lang.IllegalArgumentException - if fromIndex > toIndex
-
java.lang.ArrayIndexOutOfBoundsException - if fromIndex <
0 or toIndex > a.length
fill
public static void fill(float[] a,
float val)
-
Assigns the specified float value to each element of the specified array
of floats.
-
Parameters:
-
a - the array to be filled.
-
val - the value to be stored in all elements of the array.
fill
public static void fill(float[] a,
int fromIndex,
int toIndex,
float val)
-
Assigns the specified float value to each element of the specified range
of the specified array of floats. The range to be filled extends from index
fromIndex, inclusive, to index toIndex, exclusive. (If
fromIndex==toIndex, the range to be filled is empty.)
-
Parameters:
-
a - the array to be filled.
-
fromIndex - the index of the first element (inclusive) to be filled
with the specified value.
-
toIndex - the index of the last element (exclusive) to be filled
with the specified value.
-
val - the value to be stored in all elements of the array.
-
Throws:
-
java.lang.IllegalArgumentException - if fromIndex > toIndex
-
java.lang.ArrayIndexOutOfBoundsException - if fromIndex <
0 or toIndex > a.length
fill
public static <T> void fill(T[] a,
T val)
-
Assigns the specified Object reference to each element of the specified
array of Objects.
-
Parameters:
-
a - the array to be filled.
-
val - the value to be stored in all elements of the array.
fill
public static <T> void fill(T[] a,
int fromIndex,
int toIndex,
T val)
-
Assigns the specified Object reference to each element of the specified
range of the specified array of Objects. The range to be filled extends
from index fromIndex, inclusive, to index toIndex, exclusive.
(If fromIndex==toIndex, the range to be filled is empty.)
-
Parameters:
-
a - the array to be filled.
-
fromIndex - the index of the first element (inclusive) to be filled
with the specified value.
-
toIndex - the index of the last element (exclusive) to be filled
with the specified value.
-
val - the value to be stored in all elements of the array.
-
Throws:
-
java.lang.IllegalArgumentException - if fromIndex > toIndex
-
java.lang.ArrayIndexOutOfBoundsException - if fromIndex <
0 or toIndex > a.length
asList
public static <T> java.util.List<T> asList(T[] a)
-
Returns a fixed-size list backed by the specified array. (Changes to the
returned list "write through" to the array.) This method acts as bridge
between array-based and collection-based APIs, in combination with Collection.toArray.
The returned list is serializable and implements RandomAccess.
-
Parameters:
-
a - the array by which the list will be backed.
-
Returns:
-
a list view of the specified array.
-
See Also:
-
Collection#toArray()