Emile beat me to it, but here goes anyway...
On 10/10/2010 3:35 PM, Josep M. Fontana wrote:
Hi,
First let me apologize for taking so long to acknowledge your answers
and to thank you (Eduardo, Peter, Greg, Emile, Joel and Alan, sorry if
I left anyone) for your help and your time.
One of the reasons I took so long in responding (besides having gotten
busy with some urgent matters related to my work) is that I was a bit
embarrassed at realizing how poorly I had defined my problem.
As Alan said, I should at least have told you which operations were
giving me a headache. So I went back to my Python reference books to
try to write some code and thus be able to define my problems more
precisely. Only after I did that, I said to myself, I would come back
to the list with more specific questions.
The only problem is that doing this made me painfully aware of how
little Python I know. Well, actually my problem is not so much that I
don't know Python as that I have very little experience programming in
general. Some years ago I learned a little Perl and basically I used
it to do some text manipulation using regular expressions but that's
all my experience. In order to learn Python, I read a book called
"Beginning Python: From Novice to Professional" and I was hoping that
just by starting to use the knowledge I had supposedly acquired by
reading that book to solve real problems related to my project I would
learn. But this turned out to be much more difficult than I had
expected. Perhaps if I had worked through the excellent book/tutorial
Alan has written (of which I was not aware when I started), I would be
better prepared to confront this problem.
Anyway (sorry for the long intro), since Emile laid out the problem
very clearly, I will use his outline to point out the problems I'm having:
Emile says:
--------------
Conceptually, you'll need to:
-a- get the list of file names to change then for each
-b- determine the new name
-c- rename the file
For -a- you'll need glob. For -c- use os.rename. -b- is a bit more
involved. To break -b- down:
-b1- break out the x-xx portion of the file name
-b2- look up the corresponding year in the other file
-b3- convert the year to the century-half structure
-b4- put the pieces together to form the new file name
For -b2- I'd suggest building a dictionary from your second files
contents as a first step to facilitate the subsequent lookups.
---------------------
OK. Let's start with -b- . My first problem is that I don't really
know how to go about building a dictionary from the file with the
comma separated values. I've discovered that if I use a file method
called 'readlines' I can create a list whose elements would be each of
the lines contained in the document with all the codes followed by
comma followed by the year. Thus if I do:
fileNameCentury =
open(r'/Volumes/DATA/Documents/workspace/GCA/CORPUS_TEXT_LATIN_1/FileNamesYears.txt').readlines()
Where 'FileNamesYears.txt' is the document with the following info:
A-01, 1278
A-02, 1501
...
N-09, 1384
I get a list of the
form ['A-01,1374\rA-02,1499\rA-05,1449\rA-06,1374\rA-09, ...]
I'm guessing that you are running on a Linux system and that the file
came from a Mac. This is based on the fact that \r appears in the string
instead of acting as a line separator.
Regardless -
dct = {}
fileNameCentury = fileNameCentury.split('\r') # gives you ['A-01,1374',
'A-02,1499', 'A-05,1449', 'A-06,1374', 'A-09, ...]
for pair in fileNameCentury:
key,value = pair.split(',')
dct[key] = value
Greg mentioned the csv module. I checked the references but I could
not see any way in which I could create a dictionary using that module.
True - the csv reader is just another way to get the list of pairs.
Once I have the dictionary built, what I would have to do is use the
os module (or would it be the glob module?) to get a list of the file
names I want to change and build another loop that would iterate over
those file names and, if the first part of the name (possibly
represented by a regular expression of the form r'[A-Z]-[0-9]+')
matches one of the keys in the dictionary, then a) it would get the
value for that key, b) would do the numerical calculation to determine
whether it is the first part of the century or the second part and c)
would insert the string representing this result right before the
extension .txt.
In the abstract it sounds easy, but I don't even know how to start.
Doing some testing with glob I see that it returns a list of strings
representing the whole paths to all the files whose names I want to
manipulate. But in the reference documents that I have consulted, I
see no way to change those names. How do I go about inserting the
information about the century right before the substring '.txt'?
Suppose fn = "blah.txt"
fn2 = f
As you see, I am very green. My embarrassment at realizing how basic
my problems were made me delay writing another message but I decided
that if I don't do it, I will never learn.
Again, thanks so much for all your help.
Josep M.
Message: 2
Date: Sat, 2 Oct 2010 17:56:53 +0200
From: "Josep M. Fontana" <josep.m.font...@gmail.com
<mailto:josep.m.font...@gmail.com>>
To: tutor@python.org <mailto:tutor@python.org>
Subject: [Tutor] Using contents of a document to change file names
Message-ID:
<aanlktikjofyhiel70e=-bae_pedc0ng+igy3j+qo+...@mail.gmail.com
<mailto:bae_pedc0ng%2bigy3j%2bqo%2b...@mail.gmail.com>>
Content-Type: text/plain; charset="iso-8859-1"
Hi,
This is my first posting to this list. Perhaps this has a very
easy answer
but before deciding to post this message I consulted a bunch of Python
manuals and on-line reference documents to no avail. I would be very
grateful if someone could lend me a hand with this.
Here's the problem I want to solve. I have a lot of files with the
following
name structure:
A-01-namex.txt
A-02-namey.txt
...
N-09-namez.txt
These are different text documents that I want to process for an
NLP project
I'm starting. Each one of the texts belongs to a different century
and it is
important to be able to include the information about the century
in the
name of the file as well as inside the text.
Then I have another text file containing information about the
century each
one of the texts was written. This document has the following
structure:
A-01, 1278
A-02, 1501
...
N-09, 1384
What I would like to do is to write a little script that would do the
following:
. Read each row of the text containing information about the
centuries each
one of the texts was written
. Change the name of the file whose name starts with the code in
the first
column in the following way
A-01-namex.txt --> A-01-namex_13-2.txt
Where 13-1 means: 13th 2nd half. Obviously this information
would com
from the second column in the text: 1278 (the first two digits + 1 =
century; if the 3rd and 4th digits > 50, then 2; if < 50 then 1)
Then in the same script or in a new one, I would need to open each
one of
the texts and add information about the century they were written
on the
first line preceded by some symbol (e.g @13-2)
I've found a lot of information about changing file names (so I
know that I
should be importing the os module), but none of the examples that
were cited
involved getting the information for the file changing operation
from the
contents of a document.
As you can imagine, I'm pretty green in Python programming and I
was hoping
the learn by doing method would work. I need to get on with this
project,
though, and I'm kind of stuck. Any help you guys can give me will
be very
helpful.
Josep M.
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