Manipulation of variable length prefix string

Question

Very new to Python, and finding a tonne of great Qs and As on this site. Thank you all. Here is my dilemma:

I have a tree of locations to recursively search and move data of certain types (if they exist) and have found lots draw upon for this. My issue is with naming conventions. There is a standard format for names in which the prefix is 3 or 4 chars (some of each), name is several, suffix is four chars. Some names use an '_' as a delimiter (PLAN_someFile_to_work_ZZTT, or FOR_someOtherFile_XXYY. (PLAN,FOR - are prefix....ZZTT,XXYY - are suffix)

Here's the question: How do I split this into the three elements cleanly or 'Pythonicly' into prefix, fName, and Suffix? fName length varies and needs the '_' if it is there. I've been able to manipulate and remove '_', however then get tripped up with the prefix length being 3 or 4 chars when it comes to trying to obtain only fName (with or without the "_".) I get tripped and cannot chose the correct number of chars.

Oh, I can extract the Prefix fine, and check its existence in a tuple of legal values. Is there a way to select the Prefix from that Tuple easily? I'd be able to use that instead or trying to parse it from the file, as an option.

Code is test code. Print statements are for dev benefit and will not appear in final code. Some of the tests are for my comprehension on how Py handles this stuff. Thank you.

 for dirName, subdirList, fileList in os.walk(rootDir):
    print('Found directory: %s' % dirName)
    if dirName.lower().endswith('.xxx'):
        print('\n %s is a Database. ' % dirName)
        BADrop = ntpath.basename(dirName)
        print ('%s is variable BADrop. ' %BADrop)
        dropName = remove(BADrop, '_')
        print ('%s is variable dropName. ' %dropName)
        NST = BADrop.split('_') [0]
        NSP = BADrop.split('_') [-1]
        NSP = os.path.splitext(NSPrj) [0]
        NSt = os.path.splitext(BADrop) [1]
        abc = dropName[4:-8]
        if NST in pubTheme2: #pubTheme2 is a tuple list of legit values for the Prefix
            print ('%s is variable NST. ' %NST)
            print ('%s is variable NSP. ' %NSP)
            print ('%s is variable NSt. ' %NSt)
            print ('%s is variable abc. ' %abc)

http://stackoverflow.com/questions/7539959/python-finding-whether-a-string-starts-with-one-of-a-lists-variable-length-pre Will this work for Me? Just found this after I asked? If it will, I need a little more layman in the explanation...... Thanks, Breton01 — Breton01, Jun 24 '15 at 16:43

maccartm · Answer 1 · 2015-06-24T18:43:29.287

0

x = "PLAN_someFile_to_work_ZZTT"
y = "FOR_someOtherFile_XXYY"

def split(x):
    z = x.split("_")
    z[1] = "_".join(z[1:-1])
    del(z[2:-1])
    return z

print split(x)
print split(y)

Does something like this work for you?

PS, if you don't want the underscores to remain in the "middle" portion, simply change "_".join(z[1:-1]) to "".join(z[1:-1]). Will work either way.

edited Jun 24 '15 at 18:43

answered Jun 24 '15 at 16:49

maccartm

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Sorry maccartm. I tried this and it didn't work. z came back from the function empty. I also tried the post I placed a link to in the first comment. That post gets me a little further, but it ends up removing the prefix in the process. I need to retain that as a variable to help in determining the destination path to move the files into as part oif processing. – Breton01 Jun 24 '15 at 17:41
Add `return z` if you want it returned; I simply printed it in my example – maccartm Jun 24 '15 at 17:46
Using the code as edited works fine for me, care to post how you have it? The two outputs I get are `['PLAN', 'someFile_to_work', 'ZZTT']` and `['FOR', 'someOtherFile', 'XXYY']` – maccartm Jun 24 '15 at 18:43
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I was away yesterday, Thanks maccartm, You are correct with what I provided, and I will post my solution once I work thru and have a better understanding. I posted items that have the "_" char in the name and since this is optional, I need to test and branch. What you provided is certainly going to be central part of the solution, just not the complete one. – Breton01 Jun 26 '15 at 16:13

Manipulation of variable length prefix string

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