How can I insert elements of one array into second one?

Question

int nums1[] = {1,2,3,0,0,0}; //instead of zeros i want to add elements of nums2
int nums2[] = {2,5,6};
for(int i=3;i<nums1.length;i++){
    for(int j=0;j<nums2.length;j++){
        nums1[i]=nums2[j];
    }
}

System.out.println(Arrays.toString(nums1));

The output I want is (sorted)

[1,2,2,3,5,6]

but my output is

[1, 2, 3, 6, 6, 6].

https://docs.oracle.com/javase/7/docs/api/java/lang/System.html#arraycopy(java.lang.Object,%20int,%20java.lang.Object,%20int,%20int) — fantaghirocco, Nov 11 '21 at 10:01
Does this answer your question? [Copy arrays Java](https://stackoverflow.com/questions/20003165/copy-arrays-java) — fantaghirocco, Nov 11 '21 at 10:02
this question look like similar to yous https://stackoverflow.com/q/80476/9181430 — Rohit Kumar, Nov 11 '21 at 10:10

score 0 · Accepted Answer · answered Nov 11 '21 at 10:15

you don't want a nested loop. A single loop with multiple indexes is what you are after.

import org.junit.jupiter.api.Test;

import java.util.Arrays;

import static org.assertj.core.api.Assertions.assertThat;

public class ReplaceArrayItems {
    @Test
    void testReplaceItems() {
        int nums1[] = {1, 2, 3, 0, 0, 0}; //instead of zeros i want to add elements of nums2
        int nums2[] = {2, 5, 6};
        for (int i = 3, j = 0; i < nums1.length && j < nums2.length; i++, j++) {
            nums1[i] = nums2[j];
        }

        assertThat(nums1).isEqualTo(new int[]{1, 2, 3, 2, 5, 6});
        System.out.println(Arrays.toString(nums1));
    }
}

score 0 · Answer 2 · answered Nov 11 '21 at 10:22

I think what you're looking for is something like this:

int nums1[] = {1, 2, 3, 0, 0, 0};
int nums2[] = {2, 5, 6};
for (int i = 0, j = 0; i < nums1.length && j < nums2.length; i++)
    if(nums1[i] == 0)
        nums1[i] = nums2[j++];

Arrays.sort(nums1);
System.out.println(Arrays.toString(nums1));

How can I insert elements of one array into second one?

2 Answers2