php - Regex - Remove all matches leaving the last

Question

I need a regex to remove dots in an number but just leaving the last. Example:

12312.123132.12312.131.3131.3123.13123.1231

to

12312123132123121313131312313123.1231

I tried some expressions but none worked.

Answer 1

In addition to the other answers, here is one more

[.](?!d*$)
or
[.](?![^.]*$)