split with regex in java resulting an empty element

Question

I am trying to split a String array and use delimiters to remove any whitespace (including \t) but I am getting an empty element "" for some reason.

My Code:

String temp = "    x = x + 9";
String[] tempArr = temp.split("\\s+");

The result I am getting:

tempArr[0] = ""
tempArr[1] = "x"
tempArr[2] = "="
...

I do not understand why I am getting an empty element in the first index of the array.

Use .trim() before .split(..) to get rid of leading and trailing white spaces. — Pshemo
– Pshemo, Commented Apr 21, 2019 at 9:25
"I do not understand why I am getting an empty element in the first index of the array." what would you expect to get as result of "AxB".split("x")? And what in case of "xAxB".split("x")? Now simply change x with space. — Pshemo
– Pshemo, Commented Apr 21, 2019 at 9:38
Possible duplicate of How to remove empty results after splitting with regex in Java? — Progman
– Progman, Commented Apr 21, 2019 at 12:16

Pshemo · Accepted Answer · 2019-04-21 09:30:56Z

2

Change split("\s+") to split("\\s+") and use trim() earlier to get rid of all leading and trailing extra spaces

String[] tempArr = temp.trim().split("\\s+");

edited Apr 21, 2019 at 9:30

Pshemo

125k26 gold badges194 silver badges280 bronze badges

answered Apr 21, 2019 at 9:08

PRC_noob

841 silver badge5 bronze badges

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

1 Comment

Pshemo Over a year ago

My bad, I only focused on changing \s to \\s (which is unnecessary IMO and can't solve OP real problem because he must be using \\s to get any result, so there is no \s in his code) and missed fact that you also suggested using trim() method which was proper solution here. Sorry for downvote, fixed it.

Michal Horvath · Accepted Answer · 2019-04-21 09:30:04Z

0

You are using "\\s+" are a delimiter and in your given string " x = x + 9" there are spaces in front of the string, that means the first set of spaces is separating empty word and x.

I will try to give you some example not using spaces:

String temp = ",a,b,c";
String[] tempArr = temp.split(",");

Will result as:

tempArr[0] = ""
tempArr[1] = "a"
tempArr[2] = "b"
tempArr[2] = "c"

Do you see why? Because in front of the first "," there is empty string. It's same with spaces.

If you don't want to have first element empty, use function .trim() as @PRC_noob and @Pshemo already suggested. It will remove spaces from the beginning and the end of your string.

answered Apr 21, 2019 at 9:30

Michal Horvath

1837 bronze badges

Collectives™ on Stack Overflow

split with regex in java resulting an empty element

2 Answers 2

1 Comment

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related