[Tutor] Replacing the string in a file

[vanam]

Thanks for your mail.

As you have suggested i have  changed the mode to 'rw' but it is
throwing up an error as below

*******************
IOError: [Errno 22] invalid mode ('rw') or filename: 'data.txt'
*******************
I am using python 2.6.4.

But Script is managed to pass with 'a+' mode/r+ mode.

log = open('data.txt','r+/a+')
for x in log:
     x = x.replace('Python','PYTHON')
     print x,
log.close()

It had properly written and replaced Python to PYTHON.

Thanks for your suggestion.



On Fri, Jan 22, 2010 at 12:42 PM, Shashwat Anand
<anand.shashwat at gmail.com> wrote:
> You can try it by reading all data as string, replacing the string and then
> write it to target file via opeing it in +w mode.
>
> f = open('data.txt', 'rw').read().replace('Python', 'PYTHON')
> f1 = open('data.txt',
> 'w')
> f1.write(f)
>
> HTH
>
>
> On Fri, Jan 22, 2010 at 12:14 PM, vanam <raghavendra.gv.vanam at gmail.com>
> wrote:
>>
>> Hi all,
>>
>> I have been trying to write a script where in it has to replace a
>> particular string in a file and write back to the file without intact
>> of the contents
>>
>> I have tried below mentioned steps, but of no avail:
>>
>> 1. Created a file by name data.txt and included some text (For
>> instance,
>>
>> ************************************************************************
>> Then, I started searching for a good book on Python. I couldn't find
>> any! I did find some O'Reilly books
>> but they were either too expensive or were more like a reference
>> manual than a guide. So, I settled for
>> the documentation that came with Python. However, it was too brief and
>> small. It did give a good idea
>> about Python but was not complete. I managed with it since I had
>> previous programming experience, but
>> it was unsuitable for newbies.
>> ************************************************************************
>>
>> 2.Read the file contents (For this opened the file in read mode -- log
>> = open('data.txt','r')
>>
>> 3.Iterated through the text using for loop for reading the contents in
>> the file -- for x in log:
>>
>> 4.Replaced the word  Python with PYTHON as indicated --- x  =
>> x.replace('Python','PYTHON')
>>
>> 6.printed the full contents -- It had printed the full contents by
>> replacing the word Python to PYTHON
>>
>> Python string did not get changed to PYTHON for the reasons that i did
>> not open the file in write mode and written the string
>>
>> [Query]: How to write Python string to PYTHON to that file without
>> intact of the full contents
>>
>> I was successful in routing the contents (with changed string to
>> PYTHON) to a different file.
>>
>> And i am aware that opening the file in write mode will wipe out the
>> previous contents.
>>
>> I have tried appending the content which it does but that is not my goal.
>>
>>
>> 7. Closed the files outside for loop -- log.close()
>> --
>> Raghavendra  Vanam
>> _______________________________________________
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>
>



-- 
Raghavendra  Vanam