I'm trying to use the java.util.Arrays class in JavaSE 6 but not sure how i would implement it? on an array that I have generated?
before the start of the class i have
import java.util.Arrays
The Arrays class in java. util package is a part of the Java Collection Framework. This class provides static methods to dynamically create and access Java arrays. It consists of only static methods and the methods of Object class.
The java.util.Arrays class contains a static factory that allows arrays to be viewed as lists.Following are the important points about Arrays − This class contains various methods for manipulating arrays (such as sorting and searching).
The 'Arrays' class is a member of the 'java. util' package. This is a part of the Java Collections framework and provides methods to create, access and manipulate Java arrays dynamically.
Passing Array To The Method In Java To pass an array as an argument to a method, you just have to pass the name of the array without square brackets. The method prototype should match to accept the argument of the array type. Given below is the method prototype: void method_name (int [] array);
To declare an array of integers, you start with:
int[] myArray;
To instantiate an array of ten integers, you can try:
myArray = new int[10];
To set values in that array, try:
myArray[0] = 1; // arrays indices are 0 based in Java
Or at instantiation:
int[] myArray2 = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
To get values from the array, try:
System.out.println(myArray[0]);
To print all the values in an array, try:
// go from 0 to one less than the array length, based on 0 indexing
for(int i = 0; i < myArray2.length; i++) {
System.out.println(myArray2[i]);
}
For more information, the tutorial from Sun/Oracle will be of great help. You can also check out the Java language specification on Arrays.
java.util.Arrays contains a bunch of static methods. Static methods belong to the class and do not require an instance of the class in order to be called. Instead they are called with the class name as a prefix.
So you can do things like the following:
// print a string representation of an array
int[] myArray = {1, 2, 3, 4};
System.out.println(Arrays.toString(myArray));
Or
// sort a list
int[] unsorted = {3, 4, 1, 2, 5, 7, 6};
Arrays.sort(unsorted);
Well let's say you have an array
int[] myArray = new int[] { 3, 4, 6, 8, 2, 1, 9};
And you want to sort it. You do this:
// assumes you imported at the top
Arrays.sort(myArray);
Here's the whole shebang:
import java.util.Arrays;
class ArrayTest {
public static void main(String[] args) {
int[] myArray = new int[] { 3, 4, 6, 8, 2, 1, 9};
Arrays.sort(myArray);
System.out.println(Arrays.toString(myArray));
}
}
And that results in
C:\Documents and Settings\glow\My Documents>java ArrayTest
[1, 2, 3, 4, 6, 8, 9]
C:\Documents and Settings\glow\My Documents>
You have not provided enough information about what you are trying to do. java.util.Arrays
only exposes static methods, so you simply pass in your array and whatever other params are necessary for the particular method you are calling. For instance Arrays.fill(myarray,true)
would fill a boolean array with the value true
.
Here is the javadoc for java.util.Arrays
You can use a static import
import static java.util.Arrays.*;
int[] ints = {3, 4, 1, 2, 5, 7, 6};
sort(ints);
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