How to compose regex with condition in Java?

Question

Condition:

numbers can be either int or double (total 8 digits)
numbers can only be separated by spaces (one or many) and commas (0 or one)
commas can only be inside numbers (there can be no commas at the beginning and end of a line)
there may be spaces at the beginning of the line (one or many)
there may be spaces at the end of the line (one or many)

What I do:

([\s]*\d+(\.{1}\d+)?[\s\,\s]+){7}(\d+(\.{1}\d+)?[\s]*){1}
                    ^ this   ^

That's ok, except for one condition.
On this string I get true, but need false:

String s1 = " 0 , 4.4 3.2,, 4.1      2 4 1 7.7";

I can't do this:

Numbers can be separated by only one comma or no comma, but in this case there must be a space (one or many).

you can use (?:,?|\s+) for (zero or one comma) or (1 or more spaces) — Cid
– Cid, Commented Aug 29, 2020 at 23:06
1. Does "total 8 numbers" mean "total 8 digits"? 2. Try replacing [\s,\s]+ with (?:\s*,?\s*|\s+) (assuming a comma can have spaces around it) — Gryphon
– Gryphon, Commented Aug 29, 2020 at 23:08
@cid Shouldn't it be (?:,|\s+)? Otherwise, the regex would match the empty string. — Turing85
– Turing85, Commented Aug 29, 2020 at 23:16

Gryphon · Accepted Answer · 2020-08-29 23:23:42Z

1

This is the one I came up with for the spaces/commas (also removed some redundant parts):

Pattern.compile("([\\s]*\\d+(\\.\\d+)?(?:\\s*,\\s*|\\s+)){7}(\\d+(\\.\\d+)?[\\s]*)");

Seems to do what you want with the sample you provided, at least. (The use of {1} is generally implied for the places you used it, so I removed those)

answered Aug 29, 2020 at 23:23

Gryphon

3841 silver badge9 bronze badges

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

Collectives™ on Stack Overflow

How to compose regex with condition in Java?

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related