string/file manipulation simple

Mel Wilson mwilson at the-wire.com
Fri Aug 1 16:19:17 CEST 2003


In article <cdac0350.0308010032.378d6f08 at posting.google.com>,
gregadelliot at hotmail.com (jeff) wrote:
>I was just creating an encryption/ decryption program in python, ive
>got no problem with the algothims or anything like that. my only
>difficulty is how to i take a file and read in each charecter and then
>preform and operation to it and then output it to another file,
>basically i just wanna know how to take a string and then perform
>actions to each charecter

   I think (untested code ahead), for small files whose
contents fit comfortably in memory:

        for character in my_input_file.read():
            my_output_file.write (modified (character))

For large files, some variant of

        characters = my_input_file.read (1024)
        while characters:
            for char in characters:
                my_output_file.write (modified (char))
            characters = my_input_file.read (1024)

with the buffer-size changed from 1024 to some better
number, if necessary.

        Regards.        Mel.




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