Regex match a whitespace table

Question

I would like to match rows of a table. There are no symbols which signal where one cell starts or ends but whitespace. Strings of characters with < 3 whitespace in between should be seen as cells.

An example row:

"           here is a $$ cell               here  another         cells I dont care about........."

This is my naive and invalid attempt in which I just want 2 cells:

\\s{5,}([^\\s{2,}]+)\\s{5,}([^\\s{2,}]+)\\s{5,}.*

Possible duplicate of [Whitespace Matching Regex - Java](http://stackoverflow.com/questions/4731055/whitespace-matching-regex-java) — Overt_Agent, Dec 23 '16 at 13:15
What about the leading/trailing spaces? Do you expect any empty cells? See [this demo, BTW](https://ideone.com/Y6HYFl). — Wiktor Stribiżew, Dec 23 '16 at 13:15
No I don't expect any empty cells. I essentially look for the first n clusters of characters. — TomTom, Dec 23 '16 at 13:17
So, is the `["here is a $$ cell", "here another", "cells I dont care about........."]` expected output then? — Wiktor Stribiżew, Dec 23 '16 at 13:20
Yes. Sorry if that was unclear. I simply need 2 matches in this case though. So I guess I'd just take the first two list elements. — TomTom, Dec 23 '16 at 13:23
Ok, I posted the answer showing how to grab the first 2 cell values. — Wiktor Stribiżew, Dec 23 '16 at 13:30

score 2 · Accepted Answer · answered Dec 23 '16 at 13:29

You may trim the input first, and then split with 3 or more whitespaces, then check if you got the first 2 cell values and use them :

String s = "           here is a $$ cell               here  another         cells I dont care about.........";
String[] res = s.trim().split("\\s{3,}");
if (res.length > 1) {
    System.out.println(res[0]); // Item 1
    System.out.println(res[1]); // Item 2, the rest is unimportant
}

See the Java demo

score 1 · Answer 2 · answered Dec 23 '16 at 13:26

This regex should do the trick hopefully:

 (?<=\s{3,}|^\s?\s?)\w[\w\W]*?(?=\s{3,}|\s?\s?$)

With Java formatting it is:

"(?<=\\s{3,}|^\\s?\\s?)\\w[\\w\\W]*?(?=\\s{3,}|\\s?\\s?$)"

What it does is it tries to match a group of characters as short as possible that starts with a non white space character (so it doesn't match a single space).Then it checks behind if there are at least 3 white spaces or the line start and then checks if there are at least 3 white spaces or the line end after the match.

It only matches one cell so just repeat the expression to match multiple cells.

You can mess around with this here: http://fiddle.re/0tmcza

Regex match a whitespace table

2 Answers2