这是我最终使用的代码:

import smtplib
from email.MIMEMultipart import MIMEMultipart
from email.MIMEBase import MIMEBase
from email import Encoders


SUBJECT = "Email Data"

msg = MIMEMultipart()
msg['Subject'] = SUBJECT 
msg['From'] = self.EMAIL_FROM
msg['To'] = ', '.join(self.EMAIL_TO)

part = MIMEBase('application', "octet-stream")
part.set_payload(open("text.txt", "rb").read())
Encoders.encode_base64(part)
    
part.add_header('Content-Disposition', 'attachment; filename="text.txt"')

msg.attach(part)

server = smtplib.SMTP(self.EMAIL_SERVER)
server.sendmail(self.EMAIL_FROM, self.EMAIL_TO, msg.as_string())

代码与Oli的帖子大致相同。

代码基于二进制文件电子邮件附件问题的帖子。

下面是Oli为python3编写的修改版本

import smtplib
from pathlib import Path
from email.mime.multipart import MIMEMultipart
from email.mime.base import MIMEBase
from email.mime.text import MIMEText
from email.utils import COMMASPACE, formatdate
from email import encoders


def send_mail(send_from, send_to, subject, message, files=[],
              server="localhost", port=587, username='', password='',
              use_tls=True):
    """Compose and send email with provided info and attachments.

    Args:
        send_from (str): from name
        send_to (list[str]): to name(s)
        subject (str): message title
        message (str): message body
        files (list[str]): list of file paths to be attached to email
        server (str): mail server host name
        port (int): port number
        username (str): server auth username
        password (str): server auth password
        use_tls (bool): use TLS mode
    """
    msg = MIMEMultipart()
    msg['From'] = send_from
    msg['To'] = COMMASPACE.join(send_to)
    msg['Date'] = formatdate(localtime=True)
    msg['Subject'] = subject

    msg.attach(MIMEText(message))

    for path in files:
        part = MIMEBase('application', "octet-stream")
        with open(path, 'rb') as file:
            part.set_payload(file.read())
        encoders.encode_base64(part)
        part.add_header('Content-Disposition',
                        'attachment; filename={}'.format(Path(path).name))
        msg.attach(part)

    smtp = smtplib.SMTP(server, port)
    if use_tls:
        smtp.starttls()
    smtp.login(username, password)
    smtp.sendmail(send_from, send_to, msg.as_string())
    smtp.quit()

这里目前给出的答案都不能正确地与GMail、Outlook 2016等客户机的文件名中的非ascii符号一起工作，以及其他不支持RFC 2231的客户机(例如，参见这里)。下面的Python 3代码改编自其他一些stackoverflow的答案(对不起，没有保存原始链接)和Python 2.7的odoo/openerp代码(参见ir_mail_server.py)。它可以正确地与GMail和其他设备一起工作，并且还使用SSL。

import smtplib, ssl
from os.path import basename
from email.mime.base import MIMEBase
from mimetypes import guess_type
from email.encoders import encode_base64
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText
from email.utils import COMMASPACE, formatdate
from email.charset import Charset


def try_coerce_ascii(string_utf8):
    """Attempts to decode the given utf8-encoded string
       as ASCII after coercing it to UTF-8, then return
       the confirmed 7-bit ASCII string.
 
       If the process fails (because the string
       contains non-ASCII characters) returns ``None``.
    """
    try:
        string_utf8.encode('ascii')
    except UnicodeEncodeError:
        return
    return string_utf8


def encode_header_param(param_text):
    """Returns an appropriate RFC 2047 encoded representation of the given
       header parameter value, suitable for direct assignation as the
       param value (e.g. via Message.set_param() or Message.add_header())
       RFC 2822 assumes that headers contain only 7-bit characters,
       so we ensure it is the case, using RFC 2047 encoding when needed.
 
       :param param_text: unicode or utf-8 encoded string with header value
       :rtype: string
       :return: if ``param_text`` represents a plain ASCII string,
                return the same 7-bit string, otherwise returns an
                ASCII string containing the RFC2047 encoded text.
    """
    if not param_text: return ""
    param_text_ascii = try_coerce_ascii(param_text)
    return param_text_ascii if param_text_ascii\
         else Charset('utf8').header_encode(param_text)


smtp_server = '<someserver.com>'
smtp_port = 465  # Default port for SSL
sender_email = '<sender_email@some.com>'
sender_password = '<PASSWORD>'
receiver_emails = ['<receiver_email_1@some.com>', '<receiver_email_2@some.com>']
subject = 'Test message'
message = """\
Hello! This is a test message with attachments.

This message is sent from Python."""

files = ['<path1>/файл1.pdf', '<path2>/файл2.png']


# Create a secure SSL context
context = ssl.create_default_context()

msg = MIMEMultipart()
msg['From'] = sender_email
msg['To'] = COMMASPACE.join(receiver_emails)
msg['Date'] = formatdate(localtime=True)
msg['Subject'] = subject

msg.attach(MIMEText(message))

for f in files:
    mimetype, _ = guess_type(f)
    mimetype = mimetype.split('/', 1)
    with open(f, "rb") as fil:
        part = MIMEBase(mimetype[0], mimetype[1])
        part.set_payload(fil.read())
        encode_base64(part)
    filename_rfc2047 = encode_header_param(basename(f))

    # The default RFC 2231 encoding of Message.add_header() works in Thunderbird but not GMail
    # so we fix it by using RFC 2047 encoding for the filename instead.
    part.set_param('name', filename_rfc2047)
    part.add_header('Content-Disposition', 'attachment', filename=filename_rfc2047)
    msg.attach(part)

with smtplib.SMTP_SSL(smtp_server, smtp_port, context=context) as server:
    server.login(sender_email, sender_password)
    server.sendmail(sender_email, receiver_emails, msg.as_string())

其他的答案也很好，但我还是想分享一种不同的方法，以防有人正在寻找替代方案。

主要的区别是，使用这种方法，你可以使用HTML/CSS来格式化你的邮件，所以你可以有创意，给你的电子邮件一些样式。虽然没有强制使用HTML，但仍然可以只使用纯文本。

注意，该函数接受将电子邮件发送给多个收件人，也允许附加多个文件。

我只在python2上尝试过，但我认为它在python3上也能正常工作:

import os.path
import smtplib
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText
from email.mime.application import MIMEApplication

def send_email(subject, message, from_email, to_email=[], attachment=[]):
    """
    :param subject: email subject
    :param message: Body content of the email (string), can be HTML/CSS or plain text
    :param from_email: Email address from where the email is sent
    :param to_email: List of email recipients, example: ["a@a.com", "b@b.com"]
    :param attachment: List of attachments, exmaple: ["file1.txt", "file2.txt"]
    """
    msg = MIMEMultipart()
    msg['Subject'] = subject
    msg['From'] = from_email
    msg['To'] = ", ".join(to_email)
    msg.attach(MIMEText(message, 'html'))

    for f in attachment:
        with open(f, 'rb') as a_file:
            basename = os.path.basename(f)
            part = MIMEApplication(a_file.read(), Name=basename)

        part['Content-Disposition'] = 'attachment; filename="%s"' % basename
        msg.attach(part)

    email = smtplib.SMTP('your-smtp-host-name.com')
    email.sendmail(from_email, to_email, msg.as_string())

我希望这能有所帮助!: -)

from email.mime.text import MIMEText
from email.mime.multipart import MIMEMultipart
import smtplib
import mimetypes
import email.mime.application

smtp_ssl_host = 'smtp.gmail.com'  # smtp.mail.yahoo.com
smtp_ssl_port = 465
s = smtplib.SMTP_SSL(smtp_ssl_host, smtp_ssl_port)
s.login(email_user, email_pass)


msg = MIMEMultipart()
msg['Subject'] = 'I have a picture'
msg['From'] = email_user
msg['To'] = email_user

txt = MIMEText('I just bought a new camera.')
msg.attach(txt)

filename = 'introduction-to-algorithms-3rd-edition-sep-2010.pdf' #path to file
fo=open(filename,'rb')
attach = email.mime.application.MIMEApplication(fo.read(),_subtype="pdf")
fo.close()
attach.add_header('Content-Disposition','attachment',filename=filename)
msg.attach(attach)
s.send_message(msg)
s.quit()

为了解释，你可以使用这个链接，它解释得很好 https://medium.com/@sdoshi579/to-send-an-email-along-with-attachment-using-smtp-7852e77623

from email.MIMEMultipart import MIMEMultipart
from email.MIMEText import MIMEText
from email.MIMEImage import MIMEImage
import smtplib

msg = MIMEMultipart()
msg.attach(MIMEText(file("text.txt").read()))
msg.attach(MIMEImage(file("image.png").read()))

# to send
mailer = smtplib.SMTP()
mailer.connect()
mailer.sendmail(from_, to, msg.as_string())
mailer.close()

从这里改编。