Exception handling in regex using python

[ShruthiLS]

Hi all,

I am having a regular expression to be read from the file.

regex = '(START\s*([a-zA-Z]\w*)\s*([a-zA-Z]\w*)\s*([a-zA-Z]\w*)\s*([a-zA-Z]\w*)\s*VAR1(?P<var1>\s*(0|1).[0-9]\d*) VAR2(?P<var2>\s*(0|1).[0-9]\d*) VAR3(?P<var3>\s*(0|1).[0-9]\d*))'

pattern = re.search(regex,line)

How can we add exceptions to VAR1,VAR2,VAR3 if the value doesn't exists. And how to equate the value VAR1,VAR2,VAR3 to None. If the value doesn't exists.

Suggestions are appreciated.

Thank you,
Shruthi LS

[anbu23]

Do you want to match lines without "VAR1"? then try (VAR1)*