RegEx matcing numeric values with or without thousand separators

Question

I need a RegEx to match the following:

1.234.567
-1.234.789
1234567
-1234567

It should not match:

.123     (leading separator)
123..456 (two separators)

In other words, I need a RegEx to match long numeric values formatted with or without thousand separators.

Thanks!

Answer 1

Here is a more restricted answer

^-?(?!0)(?:\d+|\d{1,3}(?:\.\d{3})+)$

See it online here at Regexr

(?!0) prevents from starting with 0

\d+ allows the numbers without separator

\d{1,3}(?:.\d{3})+ is the part for the separator. Start with 1 to 3 numbers, then a separator and 3 numbers. The dot for the separator followed by 3 numbers can be repeated.

Answer 2

You could do something like

^-?([0-9]{1,3}\.?)+$

RegExr Demo