[lang-ref] ( regexp_replace_backward_reference ) ( python )

def test_regexp_replace_backward_reference():
    # \1,\2,..

    text = '05/12/2025, 08/11/2025, 28/10/2025'
    pattern = r'(\d{2})/(\d{2})/(\d{4})'
    after   = r'\3-\2-\1'

    r = re.sub(pattern, after, text)

    assert r == '2025-12-05, 2025-11-08, 2025-10-28'