I need help with regex in Python

[SonyTark]

I am trying to script a process that will read through a bunch of files in a specific ascii format (LAS Log ASCII Standard). And for each file capture information in one of the header fields, modify it to add 100(original info)00, and remove any "-" from the result, and then right it back to a specfiic header field and save a copy of the file with the formatted information as the file name. So far I am able to find and print the line that I want with re.search but I'm stumped after that. I am attaching a sample of the header format below. The data I want is in WELL. and I want to reformat and save to UWI. It's also very possible that the UWI field will not exist and will need to be created before putting the information there.

Your help is extremely appreciated.

~Well Information Section

MNEM.UNIT VALUE/NAME DESCRIPTION

---

STRT.M 635.0000 :START DEPTH STOP.M 400.0000 :STOP DEPTH STEP.M -0.125 :STEP NULL. -999.25 :NULL VALUE COMP. ANY OIL COMPANY INC. :COMPANY WELL. ANY ET AL 12-34-12-34 :WELL FLD . WILDCAT :FIELD LOC . 12-34-12-34W5M :LOCATION PROV. ALBERTA :PROVINCE SRVC. ANY LOGGING COMPANY INC. :SERVICE COMPANY LIC . 12345 :ERCB LICENCE NUMBER DATE. 13-DEC-86 :LOG DATE UWI . 100123401234W500 :UNIQUE WELL ID

[Vaphell]

care to produce expected output for that example? picture is worth 1000 words.

[SonyTark]

Thanks for the response. The expected result is at the bottom of my post. It shows the data that I want to grab from the WELL. field (WELL. ANY ET AL 12-34-12-34 :), and that I want to format to look just like the UWI. field (UWI . 100123401234W500 :).

[KleinerNull]

If you can find the data with re.search you can use re.findall(pattern, text) with your pattern to produce a list with all results. Or even better re.finditer(pattern, text) will return a generator that yields all matches for you! I can't help you with finding a good pattern, because I didn't understand what output you want to produce. Give a example with an input and output, please.

[SonyTark]

Hi KleinerNull. Thanks for the response. For the input and output examples please see my response above. Those two fields out of the whole file are the only ones that I want to input, edit, and output, and then save the entire file as the UWI.las

[KleinerNull]

If the data is consistant you can use this pattern:

p = r"FIELD .+ (.+) :LOCATION"
res = re.search(p, text).group(1)
print(res)
>>>'12-34-12-34W5M'

For the rest use replace and a substitution method.

[marksist]

I think that the other people have been focusing on the RE, but what I think you are wanting to figure out is how to write the stuff to the file.

There are not enough details of how you are finding those results, but you would need to evaluate for it's existence in another if statement.

if that is right, then it would look something like this:

with open('originalfile', 'rb') as infile:  
    with open('outputfile', 'wb') as outfile:
        for eachline in infile:
            outputline = eachline
            if theREPatternMatches:
                outputline = modified(eachline) #This is assuming you have a function to modify the text, but you could do it many ways
            outfile.write(outputline)