Java I/O Tutorial
Previously we have discussed about
Class Arrays
Declaration of Arrays:
public class Arrays
extends Object
Arrays class contains various methods for manipulating arrays (such as sorting and searching) and they are useful when working with arrays. This class also contains a static factory that allows arrays to be viewed as lists.
The asList( ) method returns a List that is backed by a specified array. In other words, both the list and the array refer to the same location. It has the following signature:
static <T> List asList(T... array)
The binarySearch( ) method uses a binary search to find a specified value.This method must be applied to sorted arrays. Here is one of its forms.
static int binarySearch(int array[ ], int value)
The copyOf( ) method returns a copy of an array and it has one of its form:
static int[ ] copyOf(int[ ] source, int len)
This class is a member of the Java Collections Framework.
Method Summary of Arrays:
Modifier and Method Name
|
Description
|
static <T> List<T> 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 key)
|
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 <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.
|
static <T> int 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 <T> T[] copyOf(T[] original, int newLength)
|
Copies the specified array, truncating or padding with nulls (if
necessary) so the copy has the specified length.
|
static <T,U> T[] 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 <T> T[] copyOfRange(T[] original, int from, int to)
|
Copies the specified range of the specified array into a new array.
|
static <T,U> T[] 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 bolean 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 into ascending numerical order.
|
static void sort(byte[] a, int fromIndex, int toIndex)
|
Sorts the specified range of the array into ascending order.
|
static void sort(char[] a)
|
Sorts the specified array into ascending numerical order.
|
static void sort(char[] a, int fromIndex, int toIndex)
|
Sorts the specified range of the array into ascending order.
|
static void sort(double[] a)
|
Sorts the specified array into ascending numerical order.
|
static void sort(double[] a, int fromIndex, int toIndex)
|
Sorts the specified range of the array into ascending order.
|
static void sort(float[] a)
|
Sorts the specified array into ascending numerical order.
|
static void sort(float[] a, int fromIndex, int toIndex)
|
Sorts the specified range of the array into ascending order.
|
static void sort(int[] a)
|
Sorts the specified array into ascending numerical order.
|
static void sort(int[] a, int fromIndex, int toIndex)
|
Sorts the specified range of the array into ascending order.
|
static void sort(long[] a)
|
Sorts the specified array into ascending numerical order.
|
static void sort(long[] a, int fromIndex, int toIndex)
|
Sorts the specified range of the array into ascending order.
|
static void sort(Object[] a)
|
Sorts the specified array of objects into ascending order, according
to the natural ordering of its elements.
|
static void sort(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(short[] a)
|
Sorts the specified array into ascending numerical order.
|
static void sort(short[] a, int fromIndex, int toIndex)
|
Sorts the specified range of the array into ascending order.
|
static <T> void sort(T[] a, Comparator<? super T> c)
|
Sorts the specified array of objects according to the order induced
by the specified comparator.
|
static <T> void 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.
|
Example of Arrays:
import java.util.Arrays;
public class ArraysExample {
static void display(int array[]) {
for(int i: array)
System.out.print(i + " ");
System.out.println();
}
public static void main(String[] args) {
// Allocate and initialize array.
int array[] = new int[10];
for(int i = 0; i < 10; i++)
array[i] = -3 * i;
// Display, sort, and display the array.
System.out.print("Original contents: ");
display(array);
Arrays.sort(array);
System.out.print("Sorted: ");
display(array);
// Fill and display the array.
Arrays.fill(array, 2, 6, -1);
System.out.print("After fill(): ");
display(array);
// Sort and display the array.
Arrays.sort(array);
System.out.print("After sorting again: ");
display(array);
// Binary search for -9.
System.out.print("The value -9 is at location ");
int index =
Arrays.binarySearch(array, -9);
System.out.println(index);
}
}
Program Output:
Original contents: 0 -3 -6 -9 -12 -15 -18 -21 -24 -27
Sorted: -27 -24 -21 -18 -15 -12 -9 -6 -3 0
After fill(): -27 -24 -1 -1 -1 -1 -9 -6 -3 0
After sorting again: -27 -24 -9 -6 -3 -1 -1 -1 -1 0
The value -9 is at location 2
Software Developer by Profession with 3.0 Yrs of Experience , through this blog i'am sharing my industrial Java Knowledge to entire world. For any question or query any one can comment below or mail me at pushkar.itsitm52@gmail.com.
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