从txt读取行。 文件，并将除第6行外的所有行写在另一行上，然后刷新第一个文件

Question

I'm trying to create a Python code that reads data from an email, saves it onto a temporary txt. file. There will be another permanent txt. file, where the temporary txt. files contents will be written in a form that skips the first 6 lines. During this loop the temporary file gets flushed, so the same data will not be written multiple times.

Here is the code I have worked with:

for part in email_message.walk():
    if part.get_content_type() == 'text/plain':
        body = part.get_payload(decode=True)
        save_string = str('C:/Email/file.txt')
        myfile = open(save_string, 'a')
        myfile.write(str(body)) ## Write to file 2 and then flush this 
        open ('C:/Email/file.txt','w+') as f:
        lines = f.readlines()
        open ('C:/Email/newfile.txt','a') as g:
        g.writelines(lines[6:])
        f.close()
        g.close()
        myfile.close()# Clear first file 
    else:
        continue

Currently the issue is that it writes the email to the first txt. file, but does not update the second txt. file. However, when I run the code again, the previous data gets written to the second txt. This is something I don't quite understand why it happens, since the order should be correct. Thanks in advance!

More of the code here:

 @view_config(route_name='update-data') def update_view(request): m = imaplib.IMAP4_SSL('imap.gmail.com') m.login('gmail@gmail.com', 'password') m.list() m.select('inbox') result, data = m.uid('search', None, 'UNSEEN') # Only unseen mail i = len(data[0].split()) #space separate string if i == 0: return Response('<h3> Data cannot be updated </h3><h4>No new emails</h4><a href="localhost:8888"> Return to the main page </a> ') for x in range(i): latest_email_uid = data[0].split()[x] result, email_data = m.uid('fetch', latest_email_uid, '(RFC822)') raw_email = email_data[0][1] raw_email_string = raw_email.decode('utf-8') email_message = email.message_from_string(raw_email_string) for part in email_message.walk(): if part.get_content_type() == 'text/plain': body = part.get_payload(decode=True) save_string = str('C:/Email/file.txt') myfile = open(save_string, 'a') myfile.write(str(body)) ## Write to file 2 and then flush this open ('C:/Email/file.txt','w+') as f: lines = f.readlines() open ('C:/Email/newfile.txt','a') as g: g.writelines(lines[6:]) f.close() g.close() myfile.close()# Clear first file else: continue return Response('<h3>Data update successful</h3>') 

EDIT

Got it working the way I want with this:

for part in email_message.walk():
    if part.get_content_type() == 'text/plain':
        body = part.get_payload(decode=True)
        with open('C:/Email/file.txt', 'a') as myfile:  # Opens file.txt and writes the email body
            myfile.write(str(body)) 
        with open('C:/Email/file.txt', 'r+') as f:  # Opens file.txt again in read mode and reads lines
            lines = f.readlines()
            with open ('C:/Email/newfile.txt','a') as g: # Writes file.txt contents to newfile.txt, starting from line 6, deletes contents of the first file
                g.writelines(lines[6:])
                f.truncate(0)
    else:
        continue

Answer 1

You need to close myfile before trying to reopen it and you should reopen it in read mode. Try something like this

for part in email_message.walk():
    if part.get_content_type() == 'text/plain':
        body = part.get_payload(decode=True)
        save_string = str('C:/Email/file.txt')
        myfile = open(save_string, 'a')
        myfile.write(str(body)) ## Write to file 2 and then flush this 
        
        open ('C:/Email/file.txt',) as f:
        lines = f.readlines()
        open ('C:/Email/newfile.txt','a') as g:
        g.writelines(lines[6:])
        f.close()
        g.close()

But it would be better to use with context manager to open your files, in which case you dont have to worry about closing files

for part in email_message.walk():
    if part.get_content_type() == 'text/plain':
        body = part.get_payload(decode=True)
        with open('C:/Email/file.txt', 'a') as myfile:
            myfile.write(str(body)) 
        with open('C:/Email/file.txt', 'r') as f:
            lines = f.readlines()
            with open ('C:/Email/newfile.txt','a') as g:
                g.writelines(lines[6:])

Answer 2

You're trying to append to a file that doesn't exist here:

   open ('C:/Email/newfile.txt','a') as g:
            g.writelines(lines[6:])

I propose you do something like this:

if os.path.exists('C:/Email/newfile.txt'):
    g = open ('C:/Email/newfile.txt','a')
else:
    g = open ('C:/Email/newfile.txt','w+')
g.writelines(lines[6:])

Answer 3

Let's take a step back and evaluate the intended goal of your code. You want it to basically parse the contents of an email file, and then write contents that are in text/plain format from line 7 and beyond. Therefore, we can safely assume that we are dealing with string types.

Now, your implementation uses a temporary file as a middleman for getting lines 7+. However, you can actually skip the usage of the temporary file by parsing the string itself and grabbing lines 7+. Simply split the string by \\n , the newline escape sequence, and then rebuild the string from lines 7+.

Let's assume the contents of your email part is:

>>> mystr = "This is\na message\nwith\nmultiple\nlines\nin the\nstring.\n\nEnd of file"

If I print this, it will show:

>>> print(mystr)
This is
a message
with
multiple
lines
in the
string.

End of file

You can simply split the string now, splitting by \\n , which returns a list where each element represents a line. From there, you can just grab lines from 7 and beyond, and rejoin the elements with a \\n .

>>> mystr_split = mystr.split('\n')
>>> mystr_split
['This is', 'a message', 'with', 'multiple', 'lines', 'in the', 'string.', '', 'End of file']
>>> to_write = '\n'.join(mystr_split[6:])
>>> to_write
'string.\n\nEnd of file'
>>> print(to_write)
string.

End of file

So, back to your question, you can simply parse the text/plain content of your email, and just write lines 7+ into one file without using a temporary file.

for part in email_message.walk():
    if part.get_content_type() == 'text/plain':
        body = part.get_payload(decode=True)
        save_string = r'C:/Email/file.txt'
        body_split = body.split('\n')
        to_write = '\n'.join(body_split[6:])
        with open(save_string, 'w') as f:
            f.write(to_write)