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

python 3的另一种方法(如果有人正在搜索):

import smtplib
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText
from email.mime.base import MIMEBase
from email import encoders

fromaddr = "sender mail address"
toaddr = "receiver mail address"

msg = MIMEMultipart()

msg['From'] = fromaddr
msg['To'] = toaddr
msg['Subject'] = "SUBJECT OF THE EMAIL"

body = "TEXT YOU WANT TO SEND"

msg.attach(MIMEText(body, 'plain'))

filename = "fileName"
attachment = open("path of file", "rb")

part = MIMEBase('application', 'octet-stream')
part.set_payload((attachment).read())
encoders.encode_base64(part)
part.add_header('Content-Disposition', "attachment; filename= %s" % filename)

msg.attach(part)

server = smtplib.SMTP('smtp.gmail.com', 587)
server.starttls()
server.login(fromaddr, "sender mail password")
text = msg.as_string()
server.sendmail(fromaddr, toaddr, text)
server.quit()

确保在你的Gmail帐户上允许“不太安全的应用程序”

下面是Python 3.6及更新版本的更新版本，使用Python标准库中经过大修的电子邮件模块的EmailMessage类。

import mimetypes
import os
import smtplib
from email.message import EmailMessage

username = "user@example.com"
password = "password"
smtp_url = "smtp.example.com"
port = 587


def send_mail(subject: str, send_from: str, send_to: str, message: str, directory: str, filename: str):
    # Create the email message
    msg = EmailMessage()
    msg['Subject'] = subject
    msg['From'] = send_from
    msg['To'] = send_to
    # Set email content
    msg.set_content(message)

    path = directory + filename

    if os.path.exists(path):
        ctype, encoding = mimetypes.guess_type(path)
        if ctype is None or encoding is not None:
            # No guess could be made, or the file is encoded (compressed), so
            # use a generic bag-of-bits type.
            ctype = 'application/octet-stream'
        maintype, subtype = ctype.split('/', 1)
        # Add email attachment
        with open(path, 'rb') as fp:
            msg.add_attachment(fp.read(),
                           maintype=maintype,
                           subtype=subtype,
                           filename=filename)

    smtp = smtplib.SMTP(smtp_url, port)
    smtp.starttls() # for using port 587
    smtp.login(username, password)
    smtp.send_message(msg)
    smtp.quit()

你可以在这里找到更多的例子。

我知道这是一个老问题，但我认为一定有一种比其他例子更简单的方法来做到这一点，因此我做了一个库，在不污染代码库的情况下干净地解决这个问题。包含附件非常简单:

from redmail import EmailSender
from pathlib import Path

# Configure an email sender
email = EmailSender(
    host="<SMTP HOST>", port=0,
    user_name="me@example.com", password="<PASSWORD>"
)

# Send an email
email.send(
    sender="me@example.com",
    receivers=["you@example.com"],
    subject="An example email"
    attachments={
        "myfile.txt": Path("path/to/a_file.txt"),
        "myfile.html": "<h1>Content of a HTML attachment</h1>"
    }
)

你也可以直接附加字节，Pandas DataFrame(根据键中的文件扩展名转换为格式)，Matplotlib图或枕头图像。这个库很可能是你需要一个电子邮件发送者的所有功能(它比附件要多得多)。

如何安装:

pip install redmail

你喜欢怎么用就怎么用。我还写了大量的文档:https://red-mail.readthedocs.io/en/latest/

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()

因为这里有很多关于Python 3的答案，但没有一个说明如何使用Python 3.6中经过彻底检查的电子邮件库，这里是从当前电子邮件示例文档中快速复制+粘贴。 (我略去了一些内容，以去除猜测正确MIME类型之类的多余内容。)

以Python >3.5为目标的现代代码不应该再使用email.message.Message API(包括各种MIMEText、MIMEMultipart、MIMEBase等类)或更老的mimetypes。

from email.message import EmailMessage
import smtplib

msg = EmailMessage()
msg["Subject"] = "Our family reunion"
msg["From"] = "me <sender@example.org>"
msg["To"] = "recipient <victim@example.net>"
# definitely don't mess with the .preamble

msg.set_content("Hello, victim! Look at these pictures")

with open("path/to/attachment.png", "rb") as fp:
    msg.add_attachment(
        fp.read(), maintype="image", subtype="png")

# Notice how smtplib now includes a send_message() method
with smtplib.SMTP("localhost") as s:
    s.send_message(msg)

The modern email.message.EmailMessage API is now quite a bit more versatile and logical than the older version of the library. There are still a few kinks around the presentation in the documentation (it's not obvious how to change the Content-Disposition: of an attachment, for example; and the discussion of the policy module is probably too obscure for most newcomers) and fundamentally, you still need to have some sort of idea of what the MIME structure should look like (though the library now finally takes care of a lot of the nitty-gritty around that). Perhaps see What are the "parts" in a multipart email? for a brief introduction.

Using localhost as your SMTP server obviously only works if you actually have an SMTP server running on your local computer. Properly getting email off your system is a fairly complex separate question. For simple requirements, probably use your existing email account and your provider's email server (search for examples of using port 587 with Google, Yahoo, or whatever you have - what exactly works depends somewhat on the provider; some will only support port 465, or legacy port 25 which is however now by and large impossible to use on public-facing servers because of spam filtering).