CODEWITHSUNDEEP
javaarrays
Carlo
Carlo

Reputation: 1177

How to delete one value from, and decrease the length of, a String array

I don't understand how to decrease the length of a String array. For example, with this code:

String[][] array = new String[5][2];

array[1][0] = "what";
array[2][0] = "is";
.....
.....
array[5][0] = "?";

How can I delete array[5][0] and get array.length to be 4, not 5?

Upvotes: 0

Views: 2583

Answers (3)

Ken Chan
Ken Chan

Reputation: 90467

If you want to remove the array element from the end , you can also use Arrays.copyOf() since jdk 1.6+

For example:

array = Arrays.copyOf(array, 4);

It just copy the original array 's first 4 elements to a new array , so it have the same effect as deleting the array[5]

If you want to remove an element from an specified index , you can use ArrayUtils.remove() from Apache Commons Lang 3 to do it .

/**Remove the element at index 3**/
array =ArrayUtils.remove(array, 3);

Upvotes: 3

Bero Windrider
Bero Windrider

Reputation: 23

Using arrays for such things is very time consuming. I can suggest these solutions:
1. Use one of the data structures provided by Java libraries. I'd go with HashMap since its structure allows mapping a value to a key (HashMap ) and it does the part of adding, finding and removing items. You can also use them for multi-level hashmaps if you need more than 2 columns (HashMap ) you can look that up.
2. Use a List or ArrayList structure. Make a list that contains arrays or a special structure you create to store your data.
3. (Not recommended) Go for the manual route. If you have a fixed-length array, you can shift the rows back to remove that row, and use an index to define the last row. If you have a dynamic-length array you'll need to reconstruct it each time you remove a row.

Upvotes: 0

wannik
wannik

Reputation: 12706

You cannot delete an item from an array.

But you can create a new array with smaller size and copy the content of the old array to the new one. Then, assign the value of the reference to the new array.

Consider using java.util.List. It has a method remove().

Upvotes: 2

Related Questions