[Tutor] Equivalent exception of os.path.exists()
bibi midi
bibsmendez at gmail.com
Tue Dec 1 06:46:40 CET 2009
Thanks to all of you that replied. Your inputs are very helpful and
informative.
On Tue, Dec 1, 2009 at 12:14 AM, Sander Sweers <sander.sweers at gmail.com>wrote:
>
> There is no exception to alert you a file already exists. Depending on
> how you open the file (mode) it will either read, write or append to
> the file. If the file exists and you open it in write mode it *will*
> overwrite the file. See [1] for more info.
>
> So what you need to do is check yourself if the file exists and make
> the python script take appriate action. For example:
>
> import os
> fname = "C:\\testfile.txt"
> if os.path.exists(fname):
> do something if exists
> else:
> do something else if not exists
>
> Greets
> Sander
>
Like i thought so, there is no exception to catch if a file already exist.
I've been browsing the many types of exceptions and cant find anything thats
close. Thank you for clarifying.
I may have misunderstood the exercise question and will have to return to it
to do another approach.
For the record below is the working copy of the script. Here i understand
how the os.path.exists() method works.
while True:
fname = raw_input('please enter filename: ')
if os.path.exists(fname):
print('ERROR: %s exists!') % fname
elif fname.isspace():
print('Space is not allowed!')
else:
print('you entered %s') % fname
break
all = [] # container list to hold user input lines
print "\nPopulate your file! \n"
quit_prompt = "[to quit enter a dot '.' by itself]--> "
while True:
entry = raw_input(quit_prompt)
if entry == '.':
break
else:
all.append(entry)
confirm = raw_input('save file to disk?(y/N)')
confirm = confirm.lower() #convert to lowercase
if confirm == 'y':
fobj = open(fname, 'w')
fobj.write('\n'.join(all))
fobj.close()
print('DONE! open %s to view your file') % fname
else:
print 'not saving to disk!'
sys.exit()
Thank you.
--
Best Regards,
bibimidi
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