[Tutor] alphabetizing a file by lines (original) (raw)
orbitz orbitz at ezabel.com
Sun Jul 18 22:25:35 CEST 2004
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Dragonfirebane seems to want to write his code in the way he has given
under the guise of learning. I'm not sure if others would agree or
disagree with me here, but I think doing such a thing is probably
counter productive with python.
I'd like to hear others suggestions but here are my thoughts.
In python, we should generally try to avoid duplicating as much code as
possible. This means making use of the standard library and 3rd party
libraries where we can. In dragonfirebane's situation he most likely
wants to learn about sorting. which is fine, however I think he'd have
more success if he took a simple case of say, implementing a high school
level sorting algorithm on a simple list to get the idea of how sorting
is done, but for something like this just using what python offers.
IMO, using large relatively complex programs to learn about relatively
simplistic problems is counter productive because you spend too much
time in silly details of implementation rather than focusing on what you
are trying to learn.
Dragonfirebane at aol.com wrote:
Hello all,
I'm trying to write a program that alphabetizes a file by the first letter on each line. I'm having some problems because as soon as the program finds a letter, it looks for the next letter, ignoring subsequent appearances of that letter. I can think of a couple ways to fix this but none of them seem to work. The first of these would be to add a special character to lines that have already been alphabetized, but file.write() writes to the end of a file and i would need to write the character at the current position in the file. This might be circumvented by creating a file for each line that is alphabetized, but that seems a bit extreme . . . The code is below. Any suggestions would be appreciated. Future concerns will be alphabetizing past the first letter. ############## def linum(): global i linu = open("%s%s" % (fn, ext), "r") i = 0 for line in linu.readlines(): i += 1 linu.close() def alph(): alp = open("alphebatized%s%s" % (fn, ext), "w") pal = open("prealp%s%s" % (fn, ext), "w") ## eventually for writing "\xfe" after a line that has been alphabetized read = open("%s%s" % (fn, ext), "r") ## same reason for this line until read.close() for line in read.read(): pal.write(line) pal.close() read.close() print i for do in range(i): falp(alp) alp.close() def falp(alp): global a read = open("prealp%s%s" % (fn, ext), "r") for line in read.readlines(): try: alpn = re.compile("%s(?!\xfe)" % alpha[a], re.IGNORECASE) falpn = alpn.match(line) if falpn: print line alp.write(line) a += 1 break except IndexError: pass import re import string i = 0 a = 0 alpha = ' '.join(string.asciiletters[:26]).split() fn = rawinput("Please enter name of file you wish to prioritize: ") ext = rawinput("Please enter extension of file you wish to prioritize: ") linum() alph() ################ Here is random.txt, the file being alphabetized: K cx c cd e X y v l f w Q z h r i T s p d m n a o j u b G Thanks in advance, Orri Email: dragonfirebane at aol.com AIM: singingxduck Programming Python for the fun of it. ------------------------------------------------------------------------
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