How to split a string preserving empty elements?

Question

When splitting "TEST/TEST/".split("/") I will get a string array of length = 2.

How can I split getting length = 3 with elements ["TEST", "TEST", ""], thus the last element being empty string?

(I want to achieve this with native Java, and with regards to performance as the split has to take place on a few million rows one after the other).

As per the Javadoc it will truncate trailing separators if you don't provide a limit. — Peter Lawrey, May 08 '15 at 14:02

score 3 · Accepted Answer · edited May 23 '17 at 11:51

3

You can parametrize the number of desired array elements with a split overload:

String input = "TEST/TEST/";
System.out.println(Arrays.toString(input.split("/", 3)));
// or: input.split("/", -1)

Output

[TEST, TEST, ]

Notes

Escaping the forward slash is not necessary
The "performance" part of your question is a little hard to answer unless you provide more details
You might want to multi-thread your procedure. In Java 7, you could use the fork/join framework
As Pshemo points out, you can use a negative int to apply the pattern...

as many times as possible and the array can have any length.

(from API).

edited May 23 '17 at 11:51

Community

answered May 08 '15 at 14:00

Mena

3

Or simply use negative limit `split(delimiterRegex, -1)` – Pshemo May 08 '15 at 14:01
@Pshemo nice one! Will add to the answer. – Mena May 08 '15 at 14:02
1

@Pshemo great, that's probably best solution to my question. – membersound May 08 '15 at 14:04

1 Answers1