Matching regex for optional values

Question

I'm trying to extract some information from web server log and it's not very structured so I run into troubles, I'm trying to match :

Example 1 :

2011-11-29 11:30:23,685 DEBUG [my.fully.qualified.package.Service] Added Action Item: M= 2  Success

Example 2 :

2011-11-29 11:30:23,685 DEBUG [my.fully.qualified.package.Service] Added Action Item: M=10  Success

This regex works for example 1 :

(\d\d\d\d-\d\d-\d\d)\s[\d|:]+,\d+\s([A-Z]+)\s\[(.+)\]\s.+:\sM=\s(\d).+

Where first group is the date, second is log level, third is class name and third one is the value of M.

You may have noticed that in example 1, after M= there is a space before digit and in the other example there is not that's why this regex is not working.

I did try something like M=[\s|d]+ but I get some more characters matched that I asked for, anyone have suggestion how to match both of these examples with one regex?

Answer 1

I believe you have some typo mistake, it should be

M=[\s|\d]+

Answer 2

M=\s?(\d).+

Allows for an optional whitespace after the =.

Answer 3

You want M=\s*(\d+) that will allow zero or more whitespace immediately after the =, but not any whitespace after the digits.