i am facing an issue in parsing the below pattern
the log file will have log importance in the form of == or <= or >= or << or >>
I am trying the below custom pattern. Some of the log msgs may not have this pattern, so I am using *
(?(=<>)*)
But the log mesages are not parsing and give 'grokparsefailure'
kindly check and suggest if the above pattern is wrong.. Thanks much
below pattern is working fine.
(?[=<>]*)
the one which I used earlier and was erroring is
(?(=<>)*)
One thing to note, there is a better way to handle the "some do, some don't" aspect of your log-data.
(?<Importance>(=<>)*)
That will match more than you want. To get the sense of 'sometimes':
((?<Importance>(=<>)*)|^)
This says, match these three characters and define the field Importance, or leave the field unset.
Second, you're matching specifically two characters, in combinations:
((?<Importance>(<|>|=){2})|^)
This should match two instances of any of the trio of characters you're looking for.
Related
I am trying to formnulate a regex to get the ids from the below two strings examples:
/drugs/2/drug-19904-5106/magnesium-oxide-tablet/details
/drugs/2/drug-19906/magnesium-moxide-tablet/details
In the first case, I should get 19904-5106 and in the second case 19906.
So far I tried several, the closes I could get is [drugs/2/drug]-.*\d but would return g-19904-5106 and g-19907.
Please any help to get ride of the "g-"?
Thank you in advance.
When writing a regex expression, consider the patterns you see so that you can align it correctly. For example, if you know that your desired IDs always appear in something resembling ABCD-1234-5678 where 1234-5678 is the ID you want, then you can use that. If you also know that your IDs are always digits, then you can refine the search even more
For your example, using a regex string like
.+?-(\d+(?:-\d+)*)
should do the trick. In a python script that would look something like the following:
match = re.search(r'.+?-(\d+(?:-\d+)*)', my_string)
if match:
my_id = match.group(1)
The pattern may vary depending on the depth and complexity of your examples, but that works for both of the ones you provided
This is the closest I could find: \d+|.\d+-.\d+
I am working on a wordle bot and I am trying to match words using regex. I am stuck at a problem where I need to look for specific permutations of a given word.
For example, if the word is "steal" these are all the permutations:
'tesla', 'stale', 'steal', 'taels', 'leats', 'setal', 'tales', 'slate', 'teals', 'stela', 'least', 'salet'.
I had some trouble creating a regex for this, but eventually stumbled on positive lookaheads which solved the issue. regex -
'(?=.*[s])(?=.*[l])(?=.*[a])(?=.*[t])(?=.*[e])'
But, if we are looking for specific permutations, how do we go about it?
For example words that look like 's[lt]a[lt]e'. The matching words are 'steal', 'stale', 'state'. But I want to limit the count of l and t in the matched word, which means the output should be 'steal' & 'stale'. 1 obvious solution is this regex r'slate|stale', but this is not a general solution. I am trying to arrive at a general solution for any scenario and the use of positive lookahead above seemed like a starting point. But I am unable to arrive at a solution.
Do we combine positive lookaheads with normal regex?
s(?=.*[lt])a(?=.*[lt])e (Did not work)
Or do we write nested lookaheads or something?
A few more regex that did not work -
s(?=.*[lt]a[tl]e)
s(?=.*[lt])(?=.*[a])(?=.*[lt])(?=.*[e])
I tried to look through the available posts on SO, but could not find anything that would help me understand this. Any help is appreciated.
You could append the regex which matches the permutations of interest to your existing regex. In your sample case, you would use:
(?=.*s)(?=.*l)(?=.*a)(?=.*t)(?=.*e)s[lt]a[lt]e
This will match only stale and slate; it won't match state because it fails the lookahead that requires an l in the word.
Note that you don't need the (?=.*s)(?=.*a)(?=.*e) in the above regex as they are required by the part that matches the permutations of interest. I've left them in to keep that part of the regex generic and not dependent on what follows it.
Demo on regex101
Note that to allow for duplicated characters you might want to change your lookaheads to something in this form:
(?=(?:[^s]*s){1}[^s]*)
You would change the quantifier on the group to match the number of occurrences of that character which are required.
I'm new to ANTL4 and I can't seem to figure out how to get lexer actions to perform properly.
I have a code snippet that looks for input text:
SIZE10 : [a-zA-Z]* {getText().length() <= 10}?
I would expect that it does not match any combinations of letters that are over 10 letters long, however what this does is treat a 10+ letter string as two different tokens, instead of just nullifying the whole set of 10+ letters. How can I get this action to nullify the whole set of letters?
In addition, where can I go to see all the different token functions I can use (other than getText())? The documentation about lexer actions is really poor. In general, I'm having a hard time figuring out what resources can give me a definitive list of everything in the language. Even an entry point into the source code for me to read would be good at this point. The documentation is too general/basic for me.
EDIT: I've figured out how to send a RuntimeException, but I don't know where to get the elements needed for a proper RecognitionException.
The predicate in a rule directs the parsing process in a way that allows to match only partial input (like in your case) or essentially switch off a part of the grammar depending on certain conditions. In your case the SIZE10 rule is matched until the predicate returns false. Everything up to this event is then returned as a match for SIZE10. After that lexing continues at the point it ended for the previous token and if that is again a letter it will again match SIZE10 as long as the predicate says it is correct. That's a bit different than what you would expect (e.g. using the predicate as an all or nothing switch).
However, if you instead want to match the full set of letters first and then check if the length is <= 10 you can do this in a listener. You can hook into the exitSIZE10() event and reject the match by throwing a recognition exception.
For the usable functions in your actions see the API documentation for ANTLR. For instance here is the one for Token which shows you other possibilities beside getText(). In your action, consider the context you have. In a lexer rule you deal with a Token, hence getText() etc. work on the token. In a parser rule you have a ParserContext instead, which also has a getText() function but that works differently (collecting all child contexts text into a comma separated list).
I am using Pex from the command line to find input values for test case generation.
I use PexObserve to record certain values during execution.
One of the values that I want to record is an XML-String.
However, when parsing the XML I receive "malformed XML" exceptions, since Pex only writes the first 255 characters into the log.
Is there a way to record the full XML string? or does PexObserve have a different type that will let me record longer texts?
Leaving this here, in case somebody at any point has the same issue.
I've found a solution that helped me.
Unfortunately the 255 character limit is set internally in static readonly fields.
Therefore I needed to use reflection.
My solution works by including the following line in the PUT:
typeof(Microsoft.Pex.Framework.PexObserve.ValueWriterManager).GetField("MaxWrittenElements").SetValue(null, 1000);
Replace the 1000 with any value you like.
BUT: remember that this is a quick-fix solution, that might not work for you.
It may have unwanted side-effects. You're also changing the number of List elements that are written, and perhaps other things.
i am trying to parse the below log
2015-07-07T17:51:30.091+0530,857,SelectAppointment,Non HTTP response code: java.net.URISyntaxException,FALSE,8917,20,20,0,1,1,byuiepsperflg01
Now I am unable to parse Non HTTP response code: java.net.URISyntaxException in one field. Please help be build the pattern
This is the pattern I'm using
%{TIMESTAMP_ISO8601:log_timestamp}\,%{INT:elapsed}\,%{WORD:label}\,%{INT:responsecode}\,%{WORD:responsemessage}\,%{WORD:success}\,%{SPACE:faliusemessage}\,%{INT:bytes}\,%{INT:grpThreads}\,%{INT:allThreads}\,%{INT:Latency}\,%{INT:SampleCount}\,%{INT:ErrorCount}\,%{WORD:Hostname}
If you paste your input and pattern into the grok debugger, it says "Compile ERROR". It might be an SO problem, but you had some weird characters in your pattern ("<200c><200b>").
The trick to building custom patterns is to start at the left side and pull one piece off at a time. With that, you would notice that this partial pattern works:
%{TIMESTAMP_ISO8601:log_timestamp},%{INT:elapsed},%{WORD:label}
but this one returns "No Matches":
%{TIMESTAMP_ISO8601:log_timestamp},%{INT:elapsed},%{WORD:label},%{INT:responsecode}
because you don't have an integer in that position.
Continue adding fields one at a time until everything you want is matched.
Note that you don't have to escape the commas.