[Tutor] dynamically creating files

[Don Arnold]

----- Original Message -----
From: "bob" <nospam at 245t.com>
To: <tutor at python.org>
Sent: Friday, November 14, 2003 8:38 AM
Subject: [Tutor] dynamically creating files


> I am creating a program and have come to a problem.
> I wish to write a class that handles file objects, ie opening, writing to,
> and closing a file. I wish to dynamically create the file name, as each
> instance would have its own file too use for processing. I am not sure on
> what syntax is required to derive a filename from the 'self' instance.
> Any tips/ TIA
>

Would something like this work? It's not too thoroughly tested, but it might
be a starting point  :

import os

def getNewFile(dirStr):
    for i in xrange(0,1000):
        testname = '/'.join([dirStr,'filer%04d' % i])
        try:
            f = open(testname,'r')
            f.close()
        except IOError:
            f = open(testname,'w')
            return (f,testname)

class Filer(object):
    def __init__(self,targetDir):
        self.myfile, self.myfilename = getNewFile(targetDir)
        print 'using ', self.myfilename
    def writeLines(self):
        for i in range(10):
            txt = 'writing line %d to %s...' % (i, self.myfilename)
            print txt
            self.myfile.write(txt+'\n')
    def closeMyFile(self):
        self.myfile.close()

if __name__ == '__main__':
    filer1 = Filer('c:/temp2')
    filer1.writeLines()
    filer1.closeMyFile()
    filer2 = Filer('c:/temp2')
    filer2.writeLines()
    filer2.closeMyFile()



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