token #0: [0-9]{4,} token #1: [0-9]* token #2: \n testing string: 123 1234 12345 0 matched token #1 :123 matched token #2 : matched token #0 :1234 matched token #2 : matched token #0 :12345 matched token #2 : matched token #1 :0 matched token #2 : testing string: 123 1234 12345 0 matched token #1 :123 matched token #2 : matched token #0 :1234 matched token #2 : matched token #0 :12345 matched token #2 : matched token #1 :0 matched token #2 :