is new.
java.lang.Objectjava.util.Arrays
public class Arrays
This class contains various methods for manipulating arrays (such as sorting and searching). This class also contains a static factory that allows arrays to be viewed as lists.
The methods in this class all throw a NullPointerException if the specified array reference is null, except where noted.
The documentation for the 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 .)
This class is a member of the
Java Collections Framework
Java Collections Framework
.
| Method Summary | ||
|---|---|---|
static
|
asList
(T... a) Returns a fixed-size list backed by the specified array. |
|
| 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
(byte[] a, int fromIndex, int toIndex, byte key)
Searches a range of 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
(char[] a, int fromIndex, int toIndex, char key)
Searches a range of 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
(double[] a, int fromIndex, int toIndex, double key)
Searches a range of 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
(float[] a, int fromIndex, int toIndex, float key)
Searches a range of 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
(int[] a, int fromIndex, int toIndex, int key)
Searches a range of the specified array of ints for the specified value using the binary search algorithm.
|
|
static int
|
binarySearch
(long[] a, int fromIndex, int toIndex, long key)
Searches a range of the specified array of longs 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
(
Object
[] a, int fromIndex, int toIndex,
Object
Searches a range of the specified array for the specified object using the binary search algorithm.
|
|
| static int |
binarySearch
(
Object
[] a,
Object
key) Searches the specified array for the specified object using the binary search algorithm. |
|
static int
|
binarySearch
(short[] a, int fromIndex, int toIndex, short key)
Searches a range of the specified array of shorts 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
|
binarySearch
(T[] a, int fromIndex, int toIndex, T key,
Comparator
<? super T> c)
Searches a range of the specified array for the specified object using the binary search algorithm.
|
|
static
|
binarySearch
(T[] a, T key,
Comparator
<? super T> c) Searches the specified array for the specified object using the binary search algorithm. |
|
| static boolean[] |
copyOf
(boolean[] original, int newLength) Copies the specified array, truncating or padding with false (if necessary) so the copy has the specified length. |
|
| static byte[] |
copyOf
(byte[] original, int newLength) Copies the specified array, truncating or padding with zeros (if necessary) so the copy has the specified length. |
|
| static char[] |
copyOf
(char[] original, int newLength) Copies the specified array, truncating or padding with null characters (if necessary) so the copy has the specified length. |
|
| static double[] |
copyOf
(double[] original, int newLength) Copies the specified array, truncating or padding with zeros (if necessary) so the copy has the specified length. |
|
| static float[] |
copyOf
(float[] original, int newLength) Copies the specified array, truncating or padding with zeros (if necessary) so the copy has the specified length. |
|
| static int[] |
copyOf
(int[] original, int newLength) Copies the specified array, truncating or padding with zeros (if necessary) so the copy has the specified length. |
|
| static long[] |
copyOf
(long[] original, int newLength) Copies the specified array, truncating or padding with zeros (if necessary) so the copy has the specified length. |
|
| static short[] |
copyOf
(short[] original, int newLength) Copies the specified array, truncating or padding with zeros (if necessary) so the copy has the specified length. |
|
static
|
copyOf
(T[] original, int newLength) Copies the specified array, truncating or padding with nulls (if necessary) so the copy has the specified length. |
|
static
|
copyOf
(U[] original, int newLength,
Class
<? extends T[]> newType) Copies the specified array, truncating or padding with nulls (if necessary) so the copy has the specified length. |
|
| static boolean[] |
copyOfRange
(boolean[] original, int from, int to) Copies the specified range of the specified array into a new array. |
|
| static byte[] |
copyOfRange
(byte[] original, int from, int to) Copies the specified range of the specified array into a new array. |
|
| static char[] |
copyOfRange
(char[] original, int from, int to) Copies the specified range of the specified array into a new array. |
|
| static double[] |
copyOfRange
(double[] original, int from, int to) Copies the specified range of the specified array into a new array. |
|
| static float[] |
copyOfRange
(float[] original, int from, int to) Copies the specified range of the specified array into a new array. |
|
| static int[] |
copyOfRange
(int[] original, int from, int to) Copies the specified range of the specified array into a new array. |
|
| static long[] |
copyOfRange
(long[] original, int from, int to) Copies the specified range of the specified array into a new array. |
|
| static short[] |
copyOfRange
(short[] original, int from, int to) Copies the specified range of the specified array into a new array. |
|
static
|
copyOfRange
(T[] original, int from, int to) Copies the specified range of the specified array into a new array. |
|
static
|
copyOfRange
(U[] original, int from, int to,
Class
<? extends T[]> newType) Copies the specified range of the specified array into a new array. |
|
| static boolean |
deepEquals
(
Object
[] a1,
Object
[] a2) Returns true if the two specified arrays are deeply equal to one another. |
|
| static int |
deepHashCode
(
Object
[] a) Returns a hash code based on the "deep contents" of the specified array. |
|
| static String |
deepToString
(
Object
[] a) Returns a string representation of the "deep contents" of the specified array. |
|
| 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
(
Object
[] a,
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
(
Object
[] a, int fromIndex, int toIndex,
Object
val) Assigns the specified Object reference to each element of the specified range of the specified array of Objects. |
|
| static void |
fill
(
Object
[] a,
Object
val) Assigns the specified Object reference to each element of the specified array of Objects. |
|
| 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 int |
hashCode
(boolean[] a) Returns a hash code based on the contents of the specified array. |
|
| static int |
hashCode
(byte[] a) Returns a hash code based on the contents of the specified array. |
|
| static int |
hashCode
(char[] a) Returns a hash code based on the contents of the specified array. |
|
| static int |
hashCode
(double[] a) Returns a hash code based on the contents of the specified array. |
|
| static int |
hashCode
(float[] a) Returns a hash code based on the contents of the specified array. |
|
| static int |
hashCode
(int[] a) Returns a hash code based on the contents of the specified array. |
|
| static int |
hashCode
(long[] a) Returns a hash code based on the contents of the specified array. |
|
| static int |
hashCode
(
Object
[] a) Returns a hash code based on the contents of the specified array. |
|
| static int |
hashCode
(short[] a) Returns a hash code based on the contents of the specified array. |
|
| 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
(
Object
Sorts the specified array of objects into ascending order, according to the
natural ordering
|
|
| static void |
sort
(
Object
Sorts the specified range of the specified array of objects into ascending order, according to the
natural ordering
|
|
| 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. |
|
static
|
sort
(T[] a,
Comparator
<? super T> c) Sorts the specified array of objects according to the order induced by the specified comparator. |
|
static
|
sort
(T[] a, int fromIndex, int toIndex,
Comparator
<? super T> c) Sorts the specified range of the specified array of objects according to the order induced by the specified comparator. |
|
| static String |
toString
(boolean[] a) Returns a string representation of the contents of the specified array. |
|
| static String |
toString
(byte[] a) Returns a string representation of the contents of the specified array. |
|
| static String |
toString
(char[] a) Returns a string representation of the contents of the specified array. |
|
| static String |
toString
(double[] a) Returns a string representation of the contents of the specified array. |
|
| static String |
toString
(float[] a) Returns a string representation of the contents of the specified array. |
|
| static String |
toString
(int[] a) Returns a string representation of the contents of the specified array. |
|
| static String |
toString
(long[] a) Returns a string representation of the contents of the specified array. |
|
| static String |
toString
(
Object
[] a) Returns a string representation of the contents of the specified array. |
|
| static String |
toString
(short[] a) Returns a string representation of the contents of the specified array. |
|
| Methods inherited from class java.lang. Object |
|---|
| clone , equals , finalize , getClass , hashCode , notify , notifyAll , toString , wait , wait , wait |
| Method Detail |
|---|
public static void sort(long[] a)
sorted
public static void sort(long[] a,
int fromIndex,
int toIndex)
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.
sorted
sorted
sorted
public static void sort(int[] a)
sorted
public static void sort(int[] a,
int fromIndex,
int toIndex)
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.
sorted
sorted
sorted
public static void sort(short[] a)
sorted
public static void sort(short[] a,
int fromIndex,
int toIndex)
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.
sorted
sorted
sorted
public static void sort(char[] a)
sorted
public static void sort(char[] a,
int fromIndex,
int toIndex)
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.
sorted
sorted
sorted
public static void sort(byte[] a)
sorted
public static void sort(byte[] a,
int fromIndex,
int toIndex)
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.
sorted
sorted
sorted
public static void sort(double[] a)
The < relation does not provide a total order on all floating-point values; although they are distinct numbers -0.0 == 0.0 is true and a NaN value compares neither less than, greater than, nor equal to any floating-point value, even itself. To allow the sort to proceed, instead of using the < relation to determine ascending numerical order, this method uses the total order imposed by Double.compareTo(java.lang.Double) . This ordering differs from the < relation in that -0.0 is treated as less than 0.0 and NaN is considered greater than any other floating-point value. For the purposes of sorting, all NaN values are considered equivalent and equal.
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.
sorted
public static void sort(double[] a,
int fromIndex,
int toIndex)
The < relation does not provide a total order on all floating-point values; although they are distinct numbers -0.0 == 0.0 is true and a NaN value compares neither less than, greater than, nor equal to any floating-point value, even itself. To allow the sort to proceed, instead of using the < relation to determine ascending numerical order, this method uses the total order imposed by Double.compareTo(java.lang.Double) . This ordering differs from the < relation in that -0.0 is treated as less than 0.0 and NaN is considered greater than any other floating-point value. For the purposes of sorting, all NaN values are considered equivalent and equal.
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.
sorted
sorted
sorted
public static void sort(float[] a)
The < relation does not provide a total order on all floating-point values; although they are distinct numbers -0.0f == 0.0f is true and a NaN value compares neither less than, greater than, nor equal to any floating-point value, even itself. To allow the sort to proceed, instead of using the < relation to determine ascending numerical order, this method uses the total order imposed by Float.compareTo(java.lang.Float) . This ordering differs from the < relation in that -0.0f is treated as less than 0.0f and NaN is considered greater than any other floating-point value. For the purposes of sorting, all NaN values are considered equivalent and equal.
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.
sorted
public static void sort(float[] a,
int fromIndex,
int toIndex)
The < relation does not provide a total order on all floating-point values; although they are distinct numbers -0.0f == 0.0f is true and a NaN value compares neither less than, greater than, nor equal to any floating-point value, even itself. To allow the sort to proceed, instead of using the < relation to determine ascending numerical order, this method uses the total order imposed by Float.compareTo(java.lang.Float) . This ordering differs from the < relation in that -0.0f is treated as less than 0.0f and NaN is considered greater than any other floating-point value. For the purposes of sorting, all NaN values are considered equivalent and equal.
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.
sorted
sorted
sorted
public static void sort(Object[] a)
natural ordering
Comparable
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.
sorted
public static void sort(Object[] a,
int fromIndex,
int toIndex)
natural ordering
Comparable
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.
sorted
sorted
sorted
public static <T> void sort(T[] a,
Comparator<? super T> c)
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.
sorted
natural ordering
public static <T> void sort(T[] a,
int fromIndex,
int toIndex,
Comparator<? super T> c)
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.
sorted
sorted
sorted
natural ordering
public static int binarySearch(long[] a,
long key)
sort(long[])
method)
searched
for
binarySearch
public static int
binarySearch
(long[] a, int fromIndex, int toIndex, long key)
Searches a range of the specified array of longs for the specified value using the binary search algorithm. The range must be sorted (as by the
sort(long[], int, int)
method) prior to making this call. If it is not sorted, the results are undefined. If the range contains multiple elements with the specified value, there is no guarantee which one will be found.
Parameters:
a - the array to be searched
fromIndex - the index of the first element (inclusive) to be searched
toIndex - the index of the last element (exclusive) to be searched
key - the value to be searched for
Returns:
index of the search key, if it is contained in the array within the specified range; otherwise,
(-(
insertion point
) - 1)
. The
insertion point
is defined as the point at which the key would be inserted into the array: the index of the first element in the range greater than the key, or
toIndex
if all elements in the range 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:
IllegalArgumentException
- if fromIndex > toIndex
ArrayIndexOutOfBoundsException
- if fromIndex < 0 or toIndex > a.length
Since:
1.6
public static int binarySearch(int[] a,
int key)
sort(int[])
method)
searched
for
binarySearch
public static int
binarySearch
(int[] a, int fromIndex, int toIndex, int key)
Searches a range of the specified array of ints for the specified value using the binary search algorithm. The range must be sorted (as by the
sort(int[], int, int)
method) prior to making this call. If it is not sorted, the results are undefined. If the range contains multiple elements with the specified value, there is no guarantee which one will be found.
Parameters:
a - the array to be searched
fromIndex - the index of the first element (inclusive) to be searched
toIndex - the index of the last element (exclusive) to be searched
key - the value to be searched for
Returns:
index of the search key, if it is contained in the array within the specified range; otherwise,
(-(
insertion point
) - 1)
. The
insertion point
is defined as the point at which the key would be inserted into the array: the index of the first element in the range greater than the key, or
toIndex
if all elements in the range 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:
IllegalArgumentException
- if fromIndex > toIndex
ArrayIndexOutOfBoundsException
- if fromIndex < 0 or toIndex > a.length
Since:
1.6
public static int binarySearch(short[] a,
short key)
sort(short[])
method)
searched
for
binarySearch
public static int
binarySearch
(short[] a, int fromIndex, int toIndex, short key)
Searches a range of the specified array of shorts for the specified value using the binary search algorithm. The range must be sorted (as by the
sort(short[], int, int)
method) prior to making this call. If it is not sorted, the results are undefined. If the range contains multiple elements with the specified value, there is no guarantee which one will be found.
Parameters:
a - the array to be searched
fromIndex - the index of the first element (inclusive) to be searched
toIndex - the index of the last element (exclusive) to be searched
key - the value to be searched for
Returns:
index of the search key, if it is contained in the array within the specified range; otherwise,
(-(
insertion point
) - 1)
. The
insertion point
is defined as the point at which the key would be inserted into the array: the index of the first element in the range greater than the key, or
toIndex
if all elements in the range 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:
IllegalArgumentException
- if fromIndex > toIndex
ArrayIndexOutOfBoundsException
- if fromIndex < 0 or toIndex > a.length
Since:
1.6
public static int binarySearch(char[] a,
char key)
sort(char[])
method)
searched
for
binarySearch
public static int
binarySearch
(char[] a, int fromIndex, int toIndex, char key)
Searches a range of the specified array of chars for the specified value using the binary search algorithm. The range must be sorted (as by the
sort(char[], int, int)
method) prior to making this call. If it is not sorted, the results are undefined. If the range contains multiple elements with the specified value, there is no guarantee which one will be found.
Parameters:
a - the array to be searched
fromIndex - the index of the first element (inclusive) to be searched
toIndex - the index of the last element (exclusive) to be searched
key - the value to be searched for
Returns:
index of the search key, if it is contained in the array within the specified range; otherwise,
(-(
insertion point
) - 1)
. The
insertion point
is defined as the point at which the key would be inserted into the array: the index of the first element in the range greater than the key, or
toIndex
if all elements in the range 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:
IllegalArgumentException
- if fromIndex > toIndex
ArrayIndexOutOfBoundsException
- if fromIndex < 0 or toIndex > a.length
Since:
1.6
public static int binarySearch(byte[] a,
byte key)
sort(byte[])
method)
searched
for
binarySearch
public static int
binarySearch
(byte[] a, int fromIndex, int toIndex, byte key)
Searches a range of the specified array of bytes for the specified value using the binary search algorithm. The range must be sorted (as by the
sort(byte[], int, int)
method) prior to making this call. If it is not sorted, the results are undefined. If the range contains multiple elements with the specified value, there is no guarantee which one will be found.
Parameters:
a - the array to be searched
fromIndex - the index of the first element (inclusive) to be searched
toIndex - the index of the last element (exclusive) to be searched
key - the value to be searched for
Returns:
index of the search key, if it is contained in the array within the specified range; otherwise,
(-(
insertion point
) - 1)
. The
insertion point
is defined as the point at which the key would be inserted into the array: the index of the first element in the range greater than the key, or
toIndex
if all elements in the range 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:
IllegalArgumentException
- if fromIndex > toIndex
ArrayIndexOutOfBoundsException
- if fromIndex < 0 or toIndex > a.length
Since:
1.6
public static int binarySearch(double[] a,
double key)
sort(double[])
method)
searched
for
binarySearch
public static int
binarySearch
(double[] a, int fromIndex, int toIndex, double key)
Searches a range of the specified array of doubles for the specified value using the binary search algorithm. The range must be sorted (as by the
sort(double[], int, int)
method) prior to making this call. If it is not sorted, the results are undefined. If the range contains multiple elements with the specified value, there is no guarantee which one will be found. This method considers all NaN values to be equivalent and equal.
Parameters:
a - the array to be searched
fromIndex - the index of the first element (inclusive) to be searched
toIndex - the index of the last element (exclusive) to be searched
key - the value to be searched for
Returns:
index of the search key, if it is contained in the array within the specified range; otherwise,
(-(
insertion point
) - 1)
. The
insertion point
is defined as the point at which the key would be inserted into the array: the index of the first element in the range greater than the key, or
toIndex
if all elements in the range 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:
IllegalArgumentException
- if fromIndex > toIndex
ArrayIndexOutOfBoundsException
- if fromIndex < 0 or toIndex > a.length
Since:
1.6
public static int binarySearch(float[] a,
float key)
sort(float[])
method)
searched
for
binarySearch
public static int
binarySearch
(float[] a, int fromIndex, int toIndex, float key)
Searches a range of the specified array of floats for the specified value using the binary search algorithm. The range must be sorted (as by the
sort(float[], int, int)
method) prior to making this call. If it is not sorted, the results are undefined. If the range contains multiple elements with the specified value, there is no guarantee which one will be found. This method considers all NaN values to be equivalent and equal.
Parameters:
a - the array to be searched
fromIndex - the index of the first element (inclusive) to be searched
toIndex - the index of the last element (exclusive) to be searched
key - the value to be searched for
Returns:
index of the search key, if it is contained in the array within the specified range; otherwise,
(-(
insertion point
) - 1)
. The
insertion point
is defined as the point at which the key would be inserted into the array: the index of the first element in the range greater than the key, or
toIndex
if all elements in the range 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:
IllegalArgumentException
- if fromIndex > toIndex
ArrayIndexOutOfBoundsException
- if fromIndex < 0 or toIndex > a.length
Since:
1.6
public static int binarySearch(Object[] a,
Object key)
natural ordering
the
sort(Object[])
method)
example, strings
ordering
searched
for
is
binarySearch
public static int
binarySearch
(
Object
[] a, int fromIndex, int toIndex,
Object
key)
Searches a range of the specified array for the specified object using the binary search algorithm. The range must be sorted into ascending order according to the
natural ordering
of its elements (as by the
sort(Object[], int, int)
method) prior to making this call. If it is not sorted, the results are undefined. (If the range contains elements that are not mutually comparable (for example, strings and integers), it
cannot
be sorted according to the natural ordering of its elements, hence results are undefined.) If the range contains multiple elements equal to the specified object, there is no guarantee which one will be found.
Parameters:
a - the array to be searched
fromIndex - the index of the first element (inclusive) to be searched
toIndex - the index of the last element (exclusive) to be searched
key - the value to be searched for
Returns:
index of the search key, if it is contained in the array within the specified range; otherwise,
(-(
insertion point
) - 1)
. The
insertion point
is defined as the point at which the key would be inserted into the array: the index of the first element in the range greater than the key, or
toIndex
if all elements in the range 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:
ClassCastException
- if the search key is not comparable to the elements of the array within the specified range.
IllegalArgumentException
- if fromIndex > toIndex
ArrayIndexOutOfBoundsException
- if fromIndex < 0 or toIndex > a.length
Since:
1.6
public static <T> int binarySearch(T[] a,
T key,
Comparator<? super T> c)
sort(T[], Comparator)
method)
searched
for
natural ordering
is
to
binarySearch
public static <T> int
binarySearch
(T[] a, int fromIndex, int toIndex, T key,
Comparator
<? super T> c)
Searches a range of the specified array for the specified object using the binary search algorithm. The range must be sorted into ascending order according to the specified comparator (as by the
sort(T[], int, int, Comparator)
method) prior to making this call. If it is not sorted, the results are undefined. If the range contains multiple elements equal to the specified object, there is no guarantee which one will be found.
Parameters:
a - the array to be searched
fromIndex - the index of the first element (inclusive) to be searched
toIndex - the index of the last element (exclusive) 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 array within the specified range; otherwise,
(-(
insertion point
) - 1)
. The
insertion point
is defined as the point at which the key would be inserted into the array: the index of the first element in the range greater than the key, or
toIndex
if all elements in the range 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:
ClassCastException
- if the range contains elements that are not
mutually comparable
using the specified comparator, or the search key is not comparable to the elements in the range using this comparator.
IllegalArgumentException
- if fromIndex > toIndex
ArrayIndexOutOfBoundsException
- if fromIndex < 0 or toIndex > a.length
Since:
1.6
public static boolean equals(long[] a,
long[] a2)
equality
equality
equal
public static boolean equals(int[] a,
int[] a2)
equality
equality
equal
public static boolean equals(short[] a,
short[] a2)
equality
equality
equal
public static boolean equals(char[] a,
char[] a2)
equality
equality
equal
public static boolean equals(byte[] a,
byte[] a2)
equality
equality
equal
public static boolean equals(boolean[] a,
boolean[] a2)
equality
equality
equal
public static boolean equals(double[] a,
double[] a2)
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.)
equality
equality
equal
public static boolean equals(float[] a,
float[] a2)
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.)
equality
equality
equal
public static boolean equals(Object[] a,
Object[] a2)
equality
equality
equal
public static void fill(long[] a,
long val)
filled
array
public static void fill(long[] a,
int fromIndex,
int toIndex,
long val)
filled
value
value
array
public static void fill(int[] a,
int val)
filled
array
public static void fill(int[] a,
int fromIndex,
int toIndex,
int val)
filled
value
value
array
public static void fill(short[] a,
short val)
filled
array
public static void fill(short[] a,
int fromIndex,
int toIndex,
short val)
filled
value
value
array
public static void fill(char[] a,
char val)
filled
array
public static void fill(char[] a,
int fromIndex,
int toIndex,
char val)
filled
value
value
array
public static void fill(byte[] a,
byte val)
filled
array
public static void fill(byte[] a,
int fromIndex,
int toIndex,
byte val)
filled
value
value
array
public static void fill(boolean[] a,
boolean val)
filled
array
public static void fill(boolean[] a,
int fromIndex,
int toIndex,
boolean val)
filled
value
value
array
public static void fill(double[] a,
double val)
filled
array
public static void fill(double[] a,
int fromIndex,
int toIndex,
double val)
filled
value
value
array
public static void fill(float[] a,
float val)
filled
array
public static void fill(float[] a,
int fromIndex,
int toIndex,
float val)
filled
value
value
array
public static void fill(Object[] a,
Object val)
filled
array
public static void fill(Object[] a,
int fromIndex,
int toIndex,
Object val)
filled
value
value
array
public static <T> T[] copyOf(T[] original,
int newLength)
public static <T,U> T[] copyOf(U[] original,
int newLength,
Class<? extends T[]> newType)
public static byte[] copyOf(byte[] original,
int newLength)
public static short[] copyOf(short[] original,
int newLength)
public static int[] copyOf(int[] original,
int newLength)
public static long[] copyOf(long[] original,
int newLength)
public static char[] copyOf(char[] original,
int newLength)
public static float[] copyOf(float[] original,
int newLength)
public static double[] copyOf(double[] original,
int newLength)
public static boolean[] copyOf(boolean[] original,
int newLength)
public static <T> T[] copyOfRange(T[] original,
int from,
int to)
The resulting array is of exactly the same class as the original array.
public static <T,U> T[] copyOfRange(U[] original,
int from,
int to,
Class<? extends T[]> newType)
public static byte[] copyOfRange(byte[] original,
int from,
int to)
public static short[] copyOfRange(short[] original,
int from,
int to)
public static int[] copyOfRange(int[] original,
int from,
int to)
public static long[] copyOfRange(long[] original,
int from,
int to)
public static char[] copyOfRange(char[] original,
int from,
int to)
public static float[] copyOfRange(float[] original,
int from,
int to)
public static double[] copyOfRange(double[] original,
int from,
int to)
public static boolean[] copyOfRange(boolean[] original,
int from,
int to)
public static <T> List<T> asList(T... a)
This method also provides a convenient way to create a fixed-size list initialized to contain several elements:
List<String> stooges = Arrays.asList("Larry", "Moe", "Curly");
public static int hashCode(long[] a)
The value returned by this method is the same value that would be obtained by invoking the hashCode method on a List containing a sequence of Long instances representing the elements of a in the same order. If a is null , this method returns 0.
public static int hashCode(int[] a)
The value returned by this method is the same value that would be obtained by invoking the hashCode method on a List containing a sequence of Integer instances representing the elements of a in the same order. If a is null , this method returns 0.
public static int hashCode(short[] a)
The value returned by this method is the same value that would be obtained by invoking the hashCode method on a List containing a sequence of Short instances representing the elements of a in the same order. If a is null , this method returns 0.
public static int hashCode(char[] a)
The value returned by this method is the same value that would be obtained by invoking the hashCode method on a List containing a sequence of Character instances representing the elements of a in the same order. If a is null , this method returns 0.
public static int hashCode(byte[] a)
The value returned by this method is the same value that would be obtained by invoking the hashCode method on a List containing a sequence of Byte instances representing the elements of a in the same order. If a is null , this method returns 0.
public static int hashCode(boolean[] a)
The value returned by this method is the same value that would be obtained by invoking the hashCode method on a List containing a sequence of Boolean instances representing the elements of a in the same order. If a is null , this method returns 0.
public static int hashCode(float[] a)
The value returned by this method is the same value that would be obtained by invoking the hashCode method on a List containing a sequence of Float instances representing the elements of a in the same order. If a is null , this method returns 0.
public static int hashCode(double[] a)
The value returned by this method is the same value that would be obtained by invoking the hashCode method on a List containing a sequence of Double instances representing the elements of a in the same order. If a is null , this method returns 0.
public static int hashCode(Object[] a)
For any two arrays a and b such that Arrays.equals(a, b) , it is also the case that Arrays.hashCode(a) == Arrays.hashCode(b) .
The value returned by this method is equal to the value that would be returned by Arrays.asList(a).hashCode() , unless a is null , in which case 0 is returned.
public static int deepHashCode(Object[] a)
For any two arrays a and b such that Arrays.deepEquals(a, b) , it is also the case that Arrays.deepHashCode(a) == Arrays.deepHashCode(b) .
The computation of the value returned by this method is similar to that of the value returned by List.hashCode() on a list containing the same elements as a in the same order, with one difference: If an element e of a is itself an array, its hash code is computed not by calling e.hashCode() , but as by calling the appropriate overloading of Arrays.hashCode(e) if e is an array of a primitive type, or as by calling Arrays.deepHashCode(e) recursively if e is an array of a reference type. If a is null , this method returns 0.
public static boolean deepEquals(Object[] a1,
Object[] a2)
Two array references are considered deeply equal if both are null , or if they refer to arrays that contain the same number of elements and all corresponding pairs of elements in the two arrays are deeply equal.
Two possibly null elements e1 and e2 are deeply equal if any of the following conditions hold:
If either of the specified arrays contain themselves as elements either directly or indirectly through one or more levels of arrays, the behavior of this method is undefined.
public static String toString(long[] a)
public static String toString(int[] a)
public static String toString(short[] a)
public static String toString(char[] a)
public static String toString(byte[] a)
public static String toString(boolean[] a)
public static String toString(float[] a)
public static String toString(double[] a)
public static String toString(Object[] a)
The value returned by this method is equal to the value that would be returned by Arrays.asList(a).toString() , unless a is null , in which case "null" is returned.
public static String deepToString(Object[] a)
The string representation consists of a list of the array's elements, enclosed in square brackets ( "[]" ). Adjacent elements are separated by the characters ", " (a comma followed by a space). Elements are converted to strings as by String.valueOf(Object) , unless they are themselves arrays.
If an element e is an array of a primitive type, it is converted to a string as by invoking the appropriate overloading of Arrays.toString(e) . If an element e is an array of a reference type, it is converted to a string as by invoking this method recursively.
To avoid infinite recursion, if the specified array contains itself as an element, or contains an indirect reference to itself through one or more levels of arrays, the self-reference is converted to the string "[...]" . For example, an array containing only a reference to itself would be rendered as "[[...]]" .
This method returns "null" if the specified array is null .