Hey there! Let's sort out that file path problem you're hitting with your email-sending code—this is such a common gotcha when working with Windows paths in Python, so you’re definitely not alone here.

The Root of the Problem #

Windows uses backslashes (\) for file paths, but in Python strings, the backslash acts as an escape character (think \n for newlines, \t for tabs). If you write your path directly like "F:\D\OneDrive\Python\Spyder\test\myfile.txt", Python will misinterpret those backslashes, leading to an invalid path error.

3 Simple Fixes for Your File Path #

Here are three easy ways to fix the path so Python reads it correctly:

1. Use a Raw String
   Add an r before your path string—this tells Python to treat backslashes as literal characters, no escaping needed:

   file_path = r"F:\D\OneDrive\Python\Spyder\test\myfile.txt"
   

2. Double Up the Backslashes
   Replace every single backslash with two backslashes (\\). This escapes the escape character, so Python reads it as a literal backslash:

   file_path = "F:\\D\\OneDrive\\Python\\Spyder\\test\\myfile.txt"
   

3. Use pathlib (Recommended for Cross-Platform Code)
   The pathlib module makes path handling way cleaner and works seamlessly across Windows, Mac, and Linux. Import it, then define your path like this:

   from pathlib import Path
   file_path = Path(r"F:\D\OneDrive\Python\Spyder\test\myfile.txt")
   # Or even use forward slashes—pathlib will handle it on Windows!
   # file_path = Path("F:/D/OneDrive/Python/Spyder/test/myfile.txt")
   

Full Working Code with Attachment #

Here’s your code updated with the path fix and complete attachment handling (I filled in the missing parts to make it runnable):

import smtplib
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText
from email.mime.base import MIMEBase
from email import encoders
from pathlib import Path  # Optional, but recommended

# Sender and recipient details
fromaddr = "your-sender-email@example.com"
toaddr = "recipient-email@example.com"

# Create the main email message
msg = MIMEMultipart()
msg['From'] = fromaddr
msg['To'] = toaddr
msg['Subject'] = "Test Email with Attachment"

# Add email body
body = "Hi there! Attached is the file you requested."
msg.attach(MIMEText(body, 'plain'))

# --- Fix the file path here ---
file_path = r"F:\D\OneDrive\Python\Spyder\test\myfile.txt"
# Or use pathlib: file_path = Path(r"F:\D\OneDrive\Python\Spyder\test\myfile.txt")

# Attach the file
try:
    with open(file_path, "rb") as attachment:
        # Create a MIMEBase object to hold the attachment
        part = MIMEBase('application', 'octet-stream')
        part.set_payload(attachment.read())

    # Encode the attachment in base64
    encoders.encode_base64(part)
    # Set the attachment header with the filename
    part.add_header('Content-Disposition', f'attachment; filename="myfile.txt"')

    # Add the attachment to the email
    msg.attach(part)
except FileNotFoundError:
    print(f"Error: Could not find file at {file_path}")
    exit()

# Send the email (example using Gmail; adjust for your email provider)
try:
    # Connect to SMTP server
    server = smtplib.SMTP('smtp.gmail.com', 587)
    server.starttls()  # Enable TLS encryption
    server.login(fromaddr, "your-app-password-or-email-password")  # Use app password for 2FA-enabled accounts

    # Convert message to string and send
    text = msg.as_string()
    server.sendmail(fromaddr, toaddr, text)
    server.quit()

    print("Email sent successfully!")
except Exception as e:
    print(f"Failed to send email: {str(e)}")

Quick Notes to Avoid Other Issues #

• Double-check that the file path is exact—even a tiny typo (like a missing folder name) will cause a FileNotFoundError.
• If you’re using Gmail with two-factor authentication enabled, you’ll need to use an app password instead of your regular email password.
• For other email providers (Outlook, Yahoo, etc.), adjust the SMTP server address and port (e.g., Outlook uses smtp.office365.com on port 587).

内容的提问来源于stack exchange，提问作者Mark Carr