Merge 3 list items

Question

I have 3 list in Java and how do I merge them?

list1 = [10,20,30] list2 = [40,50,60] list3 = [70]

Output

res = [10,40,70,20,50,30,60]

I'm familiar with writing a achieving the result but would like to know if there is any libraries that I can use it.

"I'm familiar with...", can you give us an example of what you normally do? — Jon Egeland
– Jon Egeland, Commented Feb 12, 2015 at 21:40

Community · Accepted Answer · 2017-05-23 11:43:32Z

1

res = ArrayUtils.addAll(list1, list2); res = ArrayUtils.addall(res,list3);

Also, see many more options on how to do this here.

edited May 23, 2017 at 11:43

CommunityBot

11 silver badge

answered Feb 12, 2015 at 21:41

barq

3,7114 gold badges28 silver badges40 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Community · Accepted Answer · 2017-05-23 12:27:21Z

from How to mix two arrays in Java?

int[] merge(int[]... arrays) { int length = 0; for (int[] a: arrays) { length += a.length; } int result[] = new int[length]; for (int i = 0, j = 0; j < length; ++i) { for (int[] a: arrays) { if (i < a.length) { result[j++] = a[i]; } } } return result; }

then simply

merge(list1, list2, list3)

eckes · Accepted Answer · 2015-02-13 04:37:34Z

You can use the normal Java 7 libraries:

List result = new ArrayList(); result.addAll(list1); result.addAll(list2); result.addAll(list3);`

or shorter:

List result = new ArrayList(); Collections.addAll(result, list1, list2, list3);

I guess there is also a Java 8 stream solution.

Collectives™ on Stack Overflow

Merge 3 list items

3 Answers 3

Comments

Comments

Comments

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

Comments

Comments

Linked

Related