Hi, I am using a python parser for parsing the incoming message from syslog-ng. In my log messages some fields are optional and some are not.I want to know how to handle these optional parameters in the python regual expression. for example: sample log :-> log='Sep 15 22:23:37 ecis007 codeSystemName=5 UserID="Admin"' regular expression :-> aregex=re.compile(r"(?P<destmonth>\S+) (?P<devicedate>\S+) (?P<devtime>\S+) (?P<devicename>\S+) codeSystemName=(?P<EventIDcodeSystemName>.*)") if I run the following python command then i can get all the parameters r=aregex.match(log2) but if "codeSystemName=5" is a optional parameters and it is not in some messages then my parser is not able to parse the message. log='Sep 15 22:23:37 ecis007 UserID="Admin' let me know how to write the regex for optional parameters ? Regards, Vaibhav