Get last characters up to specific character

Question

Lets say I have a string something-123.

I need to get last 5 (or less) characters of it but only up to - if there is one in the string, so the result would be like thing, but if string has no - in it, like something123 then the result would be ng123, and if string is like 123 then the result would be 123.

I know how to mach last 5 characters:

/.{5}$/

I know how to mach everything up to first -:

/[^-]*/

But I can not figure out how to combine them, and to make things worse I need to get the match without extracting it from specific groups and similar advanced regex stuff because I want to use it in SQL Anywhere, please help.

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Tank you all for the help, but looks like a complete regex solution is going to be too complicated for my problem, so I did it very simple: SELECT right(regexp_substr('something-123', '[^-]*'), 4).

Answer 1

You can use:

.{5}(?=(?:-[^-]*)?$)

See the regex demo

We match 5 symbols other than a newline only before the last - in the string or at the very end of the string ((?=(?:-[^-]*)?$)). You only need to collect the matches, no need checking groups/submatches.

UPDATE

To match any 1 to 5 characters other than a hyphen before the first hyphen (if present in the string), you can use

([^-]{1,5})(?:(?:-[^-]*)*)?$

See demo. We rely on a lookahead here, that checks if there are -+non-hyphen sequences are after the expected substring.

An faster alternative:

^[^-]*?([^-]{1,5})(?:-|$)

This regex will search for any characters other than - up to 1 to 5 such characters.

Note that here, the value we need is in Group 1.

Answer 2

Try this regex:

(.{1,5})(?:-.*|$)

Group 1 has the result you need

demo

Answer 3

How about:

(.{5})(?:-[^-]+)?$

The result is in group 1

Answer 4

One option is to group the result:

(.{4})-

Now you have captured the result but without the -.

Or using lookarounds you can:

.{4}(?=-)

which matches any 4 characters that appears before "-".