Question

I have a logfile having contains as below

log=

       Using data from (yyyy/mm/dd): 2011/8/3
       0 files queued for scanning.
       Warning: E:\test\Händler.pdf File not Found.
       Loading com, please wait. 
       1520 file scanned.

I want to write a regex to detect the Warning message because this is optional warning comming sometimes I wrote the basic regext to the data which will coming compulsory.

logd = re.compile("Using\sdata\sfrom\s\(yyyy/mm/dd\):\s(? P<Defs_Date>\d{4}/\d+/\d+)[^\w\d] ")
data =  Re.search(logd, log).groupdict()

Output will be :

{'Defs_Date': '2011/8/3'}

Since the warning is optional so how I should handle it. I am not good in writting in regex. And please suggest me any good examples or links to get master in regex.

Answer 1

One way to handle optional parts is to use regex text (optional part|). The part inside parenthesis will match either “optional part” (which can be a regex on its own) or nothing.