Get only part of an Array in Java

Question

I have an array of Integers in Java  I would like use only a part of it  I know in Python you can do something like this array index   and it returns the array from the index  Is something like this possible in Java

User · Answer

If you are using Java 1 6 or greater  you can use Arrays copyOfRange to copy a portion of the array  From the javadoc      Copies the specified range of the specified array into a new array  The initial index of the range  from  must lie between zero and original length  inclusive  The value at original from  is placed into the initial element of the copy  unless from    original length or from    to   Values from subsequent elements in the original array are placed into subsequent elements in the copy  The final index of the range  to   which must be greater than or equal to from  may be greater than original length  in which case false is placed in all elements of the copy whose index is greater than or equal to original length - from  The length of the returned array will be to - from    Here is a simple example           Program that Copies the specified range of the specified array into a new     array     CopyofRange8Array java     Author -RoseIndia Team    Date -15-May-2008     import java util    public class CopyofRange8Array       public static void main String   args             creating a short array        Object T     Rose   India   Net   Limited   Rohini                 Copies the specified  short array upto specified range          Object T1     Arrays copyOfRange T  1 5           for  int i   0  i  lt  T1 length  i                   Displaying the Copied short array upto specified range             System out println T1 i

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You could wrap your array as a list  and request a sublist of it   MyClass   array        List lt MyClass gt  subArray   Arrays asList array  subList index  array length

User · Answer

public static int   range int   array  int start  int end           int returner     new int end-start           for int x   0  x  lt   end-start-1  x                 returner x    array x start                     return returner         this is a way to do the same thing as Array copyOfRange but without importing anything

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You can try    System arraycopy sourceArray  0  targetArray  0  targetArray length     copies whole array     copies elements 1 and 2 from sourceArray to targetArray System arraycopy sourceArray  1  targetArray  0  2      See javadoc for System

User · Answer

You can use subList int fromIndex  int toIndex  method on your integers arr  something like this   import java util ArrayList  import java util List   public class Main       public static void main String   args            List lt Integer gt  arr   new ArrayList lt  gt             arr add 1           arr add 2           arr add 3           arr add 4           List lt Integer gt  partialArr   arr subList 1  3               print the subArr         for  Integer i  partialArr              System out println i                   Output will be  2 3   Note that subList int fromIndex  int toIndex  method performs minus 1 on the 2nd variable it receives  var2 - 1   i don t know exactly why  but that s what happens  maybe to reduce the chance of exceeding the size of the array

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The length of an array in Java is immutable  So  you need to copy the desired part as a new array  Use copyOfRange method from java util Arrays class   int   newArray   Arrays copyOfRange oldArray  startIndex  endIndex        startIndex is the initial index of the range to be copied  inclusive    endIndex is the final index of the range to be copied  exclusive   This index may lie outside the array    E g         index   0   1   2   3   4 int   arr    10  20  30  40  50   Arrays copyOfRange arr  0  2               returns  10  20  Arrays copyOfRange arr  1  4               returns  20  30  40  Arrays copyOfRange arr  2  arr length      returns  30  40  50   length   5

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Check out copyOfRange  and example   int   arr2   Arrays copyOfRange arr 0 3

User · Answer

Yes  you can use Arrays copyOfRange  It does about the same thing  note there is a copy   you don t change the initial array

User · Answer

You can use something like this  Arrays copyOfRange

[java] Get only part of an Array in Java?

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