How to conditional regex

Question

I want a regex that does one thing if it has 3 instances of .in the string, and something else if it has more than 3 instances.

for example

Answer 1

In Python (excuse me; but regexes are without language frontier)

import re

regx = re.compile('^([^.]*?\.){3}[^.]*?\.')

for ss in ("aaa.bbb.ccc",
           "aaa.bbb.ccc.ffffd",
           'aaa.bbb.ccc.ffffd.eee',
           'a.b.c.d.e.f.g.h.i...'):
  if regx.search(ss):
    print ss + '     has at least 4 dots in it'
  else:
    print ss + '     has a maximum of 3 dots in it'

result

aaa.bbb.ccc     has a maximum of 3 dots in it
aaa.bbb.ccc.ffffd     has a maximum of 3 dots in it
aaa.bbb.ccc.ffffd.eee     has at least 4 dots in it
a.b.c.d.e.f.g.h.i...     has at least 4 dots in it

This regex' pattern doesn't require that the entire string be analysed (no symbol $ in it). It's better on long strings.