File handling problem.

Chris Rebert clp2 at rebertia.com
Sun May 3 19:17:22 CEST 2009


On Sun, May 3, 2009 at 9:51 AM, SUBHABRATA BANERJEE
<subhakolkata1234 at gmail.com> wrote:
> Dear Group,
>
>
>
> I am working on a code like the following:
>
>
>
> from decimal import*
>
> #SAMPLE TEST PROGRAM FOR FILE
>
> def sample_file_test(n):
>
>     #FILE FOR STORING PROBABILITY VALUES
>
>     open_file=open("/python26/Newfile1.txt","r+")

Is there a reason you must output the results to the same file the
input came from? It's possible this is part of your problems.

>
>     #OPENING OF ENGLISH CORPUS
>
>     open_corp_eng=open("/python26/TOTALENGLISHCORPUS1.txt","r")
>
>     #READING THE ENGLISH CORPUS
>
>     corp_read=open_corp_eng.read()
>
>     #CONVERTING THE CORPUS FILE IN WORDS
>
>     corp_word=corp_read.split()
>
>     #EXTRACTING WORDS FROM CORPUS FILE OF WORDS
>
>     for word in corp_word:
>
>         #COUNTING THE WORD
>
>         count1=corp_word.count(word)

Note: Your program is currently O(N^2) rather than O(N) because you
re-count the number of occurrences of each word /on every occurrence
of the word/.

>         #COUNTING TOTAL NUMBER OF WORDS
>
>         count2=len(corp_word)
>
>         #COUNTING PROBABILITY OF WORD
>
>         count1_dec=Decimal(count1)
>
>         count2_dec=Decimal(count2)
>
>         getcontext().prec = 6
>
>         prob_count=count1_dec/count2_dec
>
>         print prob_count
>
>         string_of_prob_count=str(prob_count)
>
>         file_input_val=open_file.write(string_of_prob_count)
>
>         open_file.close()

You shouldn't be closing the file until the /entire loop/ has finished
writing to the file. So the previous line should be dedented.

>
>
>
> The problems I am getting:
>
> (i)                  The probability values are not being stored properly in
> file.

Also, you're currently not putting any separator between consecutive
entires, so it's all going to run together as one long line.
Have you considered using one of the std lib modules to output the
file in a well-defined human-readable format such as JSON or CSV?

> (ii)                “Newfile1.txt” is storing not the series of values but
> an arbitrary value from series 0.00000143096
>
> (iii)               As I was testing it again it gave me another error
>
> Traceback (most recent call last):
>
>   File "<pyshell#2>", line 1, in <module>
>
>     sample_file_test(1)
>
>   File "C:\Python26\testprogramforfiles1.py", line 25, in sample_file_test
>
>     file_input_val=open_file.write(string_of_prob_count)
>
> ValueError: I/O operation on closed file


Cheers,
Chris
-- 
http://blog.rebertia.com



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