Re: [Tutor] Writing to a file/changing the file name
On 2/23/2012 12:04 AM, Michael Lewis wrote: Hi everyone, I have a program where I open a file (recipe.txt), I read that file and write it to another file. I am doing some multiplying of numbers in between; however, my question is, when I name the file I am writing to, the file extension is changed, but the file name is not. What am I doing wrong? Christian gave you the answer (he fished for you) How to fish for yourself: Before posting a question do a walkthru of the program. This means pretending you are the Python interpreter and your job is to execute the program step-by-step, writing down the effect of each statement You will find many answers yourself this way, saving all of us time and energy. in the above case take the statement new_file_name = file_name + '2' and do this: file_name is recipe.txt file_name + '2' is here you pretend to be the interpreter and answer the question what is recipe.txt + 2 If you come up with anything other than recipe.txt2 then you need to review how Python works. Another idea is: when you get an unexpected result there must be a very good reason for it. Do a little hunting. Each time you solve a problem for yourself you get stronger. HTH -- Bob Gailer 919-636-4239 Chapel Hill NC ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
[Tutor] Writing to a file/changing the file name
Hi everyone,
I have a program where I open a file (recipe.txt), I read that file and
write it to another file. I am doing some multiplying of numbers in
between; however, my question is, when I name the file I am writing to, the
file extension is changed, but the file name is not. What am I doing wrong?
Code:
import Homework5_1 as multiply
def MultiplyNumbersInFile(file_name, multiplier):
'''Open file/read file/write new file that doubles all int's in the
read file'''
try:
read_file = open(file_name)
except IOError:
print I can't find file: , file_name
return
new_file_name = file_name + '2'
try:
write_file = open(new_file_name, 'w')
except IOError:
read_file.close()
print I can't open file: , new_file_name
return
for line in read_file:
new_line = line.split()
new_line = ''.join(multiply.MultiplyText(new_line, multiplier))
write_file.write(new_line + '\n')
read_file.close()
write_file.close()
def main():
file_name = raw_input('What file do you want to open? ')
multiplier = multiply.GetUserNumber()
MultiplyNumbersInFile(file_name, multiplier)
if __name__ == '__main__':
main()
What I am doing in IDLE:
What file do you want to open? recipe.txt
Enter a multiplier: 2
The file that is actually created in my directory is still named recipe;
however, the file type is now TXT2 File. How do I make it so I am updating
the file name to recipe2 instead of the file type?
--
Michael J. Lewis
___
Tutor maillist - Tutor@python.org
To unsubscribe or change subscription options:
http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Writing to a file/changing the file name
On 2012/02/23 07:04 AM, Michael Lewis wrote:
Hi everyone,
I have a program where I open a file (recipe.txt), I read that file
and write it to another file. I am doing some multiplying of numbers
in between; however, my question is, when I name the file I am writing
to, the file extension is changed, but the file name is not. What am I
doing wrong?
Code:
import Homework5_1 as multiply
def MultiplyNumbersInFile(file_name, multiplier):
'''Open file/read file/write new file that doubles all int's in the
read file'''
try:
read_file = open(file_name)
except IOError:
print I can't find file: , file_name
return
new_file_name = file_name + '2'
try:
write_file = open(new_file_name, 'w')
except IOError:
read_file.close()
print I can't open file: , new_file_name
return
for line in read_file:
new_line = line.split()
new_line = ''.join(multiply.MultiplyText(new_line, multiplier))
write_file.write(new_line + '\n')
read_file.close()
write_file.close()
def main():
file_name = raw_input('What file do you want to open? ')
multiplier = multiply.GetUserNumber()
MultiplyNumbersInFile(file_name, multiplier)
if __name__ == '__main__':
main()
What I am doing in IDLE:
What file do you want to open? recipe.txt
Enter a multiplier: 2
The file that is actually created in my directory is still named
recipe; however, the file type is now TXT2 File. How do I make it so I
am updating the file name to recipe2 instead of the file type?
--
Michael J. Lewis
___
Tutor maillist - Tutor@python.org
To unsubscribe or change subscription options:
http://mail.python.org/mailman/listinfo/tutor
That's because your `file_name` variable contains the file name and
extension. You will need to split it into it's component pieces and
then put it back together once you've changed the name, and for that you
can use os.path.splitext
import os
filename, extension = os.path.splitext('recipe.txt')
print (filename, extension)
('recipe', '.txt')
new_filename = filename + '2' + extension
print new_filename
'recipe2.txt'
--
Christian Witts
Python Developer
//
___
Tutor maillist - Tutor@python.org
To unsubscribe or change subscription options:
http://mail.python.org/mailman/listinfo/tutor
