Combine two integer arrays

Question

Is there a way to create a single array out of two  E g   int   array1    1 2 3   int   array2    4 5 6   int   array1and2   array1   array2

User · Answer

I think you have to allocate a new array and put the values into the new array. For example:

int[] array1and2 = new int[array1.length + array2.length];
int currentPosition = 0;

for( int i = 0; i < array1.length; i++) {
    array1and2[currentPosition] = array1[i];
    currentPosition++;
}

for( int j = 0; j < array2.length; j++) {
    array1and2[currentPosition] = array2[j];
    currentPosition++;
}

As far as I can tell just looking at it, this code should work.

User · Answer

You can t add them directly  you have to make a new array and then copy each of the arrays into the new one   System arraycopy is a method you can use to perform this copy   int   array1and2   new int array1 length   array2 length   System arraycopy array1  0  array1and2  0  array1 length   System arraycopy array2  0  array1and2  array1 length  array2 length     This will work regardless of the size of array1 and array2

User · Answer

Find the total size of both array and set array1and2 to the total size of both array added  Then loop array1 and then array2 and add the values into array1and2

User · Answer

Yes but it is not quite that easy   Create a third array that is the size of the two arrays combined and loop through each original array and move the items over   Also look into System arraycopy

User · Answer

NOTE  didn t test it  int   concatArray int   a  int   b      int   c   new int a length   b length     int i   0    for  int x   a    c i    x  i         for  int x   b    c i    x  i         return c

User · Answer

use ArrayUtils addAll T    T       import org apache commons lang3 ArrayUtils   AnyObject   array1        AnyObject   array2        AnyObject   mergedArray   ArrayUtils addAll array1  array2

User · Answer

Task  Given two int arrays array1 and array2 of the same length  zip should return an array that s twice as long  in which the elements of array1 and array2 are interleaved  That is  element  0 of the result array is array1 0   element  1 is array2 0   element  2 is array1 1   element  3 is array2 1   and so on   public static int    zip int     array1  int    array2      make sure both arrays have same length if  array1 length    array2 length        throw new IllegalArgumentException  Unequal array lengths - zip not possible       int    zippedArray   new int  array1 length  array2 length    int idx 1   0  int idx 2   0     for each element of first array  add to new array if index of new array is even  for  int i 0  i  lt  zippedArray length  i  2       zippedArray i   array1 idx 1       for  int i 1  i  lt  zippedArray length  i  2       zippedArray i   array2 idx 2          check contents of new array        for  int item  zippedArray       System out print item            return zippedArray

User · Answer

Here a simple function that use variable arguments   final static public int   merge final int      arrays         int size   0      for   int   a  arrays           size    a length           int   res   new int size            int destPos   0          for   int i   0  i  lt  arrays length  i                   if   i  gt  0   destPos    arrays i-1  length              int length   arrays i  length              System arraycopy arrays i   0  res  destPos  length                      return res      To use   int   array1    1 2 3   int   array2    4 5 6   int   array3    7 8 9   int   array1and2and3   merge array1  array2  array3   for   int x  array1and2and3        System out print  String format   3d   x

User · Answer

int    newArray   new int old1 length old2 length   System arraycopy  old1  0  newArray  0  old1 length   System arraycopy  old2  0  newArray  old1 length  old2 length      Don t use element-by-element copying  it s very slow compared to System arraycopy

[java] Combine two integer arrays

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