How to send email attachments?

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()

Adapted from here.

This is the code I ended up using:

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())

Code is much the same as Oli’s post.

Code based from Binary file email attachment problem post.

Here is the modified version from Oli for python 3

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()

The simplest code I could get to is:

#for attachment email
from django.core.mail import EmailMessage

    def attachment_email(request):
            email = EmailMessage(
            'Hello', #subject
            'Body goes here', #body
            '[email protected]', #from
            ['[email protected]'], #to
            ['[email protected]'], #bcc
            reply_to=['[email protected]'],
            headers={'Message-ID': 'foo'},
            )

            email.attach_file('/my/path/file')
            email.send()

It was based on the official Django documentation

Other answers are excellent, though I still wanted to share a different approach in case someone is looking for alternatives.

Main difference here is that using this approach you can use HTML/CSS to format your message, so you can get creative and give some styling to your email. Though you aren’t enforced to use HTML, you can also still use only plain text.

Notice that this function accepts sending the email to multiple recipients and also allows to attach multiple files.

I’ve only tried this on Python 2, but I think it should work fine on 3 as well:

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: ["[email protected]", "[email protected]"]
    :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())

I hope this helps! 🙂

Gmail version, working with Python 3.6 (note that you will need to change your Gmail settings to be able to send email via smtp from it:

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


def send_mail(send_from: str, subject: str, text: str, 
send_to: list, files= None):

    send_to= default_address if not send_to else send_to

    msg = MIMEMultipart()
    msg['From'] = send_from
    msg['To'] = ', '.join(send_to)  
    msg['Subject'] = subject

    msg.attach(MIMEText(text))

    for f in files or []:
        with open(f, "rb") as fil: 
            ext = f.split('.')[-1:]
            attachedfile = MIMEApplication(fil.read(), _subtype = ext)
            attachedfile.add_header(
                'content-disposition', 'attachment', filename=basename(f) )
        msg.attach(attachedfile)


    smtp = smtplib.SMTP(host="smtp.gmail.com", port= 587) 
    smtp.starttls()
    smtp.login(username,password)
    smtp.sendmail(send_from, send_to, msg.as_string())
    smtp.close()

Usage:

username = '[email protected]'
password = 'top-secret'
default_address = ['[email protected]'] 

send_mail(send_from= username,
subject="test",
text="text",
send_to= None,
files= # pass a list with the full filepaths here...
)

To use with any other email provider, just change the smtp configurations.

Another way with python 3 (If someone is searching):

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()

Make sure to allow “less secure apps” on your Gmail account

Below is combination of what I’ve found from SoccerPlayer’s post Here and the following link that made it easier for me to attach an xlsx file. Found Here

file = 'File.xlsx'
username=''
password=''
send_from = ''
send_to = 'recipient1 , recipient2'
Cc = 'recipient'
msg = MIMEMultipart()
msg['From'] = send_from
msg['To'] = send_to
msg['Cc'] = Cc
msg['Date'] = formatdate(localtime = True)
msg['Subject'] = ''
server = smtplib.SMTP('smtp.gmail.com')
port = '587'
fp = open(file, 'rb')
part = MIMEBase('application','vnd.ms-excel')
part.set_payload(fp.read())
fp.close()
encoders.encode_base64(part)
part.add_header('Content-Disposition', 'attachment', filename='Name File Here')
msg.attach(part)
smtp = smtplib.SMTP('smtp.gmail.com')
smtp.ehlo()
smtp.starttls()
smtp.login(username,password)
smtp.sendmail(send_from, send_to.split(',') + msg['Cc'].split(','), msg.as_string())
smtp.quit()

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()

For explanation, you can use this link it explains properly
https://medium.com/@sdoshi579/to-send-an-email-along-with-attachment-using-smtp-7852e77623

from email.mime.multipart import MIMEMultipart
from email.mime.image import MIMEImage
from email.mime.text import MIMEText
import smtplib

msg = MIMEMultipart()

password = "password"
msg['From'] = "from_address"
msg['To'] = "to_address"
msg['Subject'] = "Attached Photo"
msg.attach(MIMEImage(file("abc.jpg").read()))
file = "file path"
fp = open(file, 'rb')
img = MIMEImage(fp.read())
fp.close()
msg.attach(img)
server = smtplib.SMTP('smtp.gmail.com: 587')
server.starttls()
server.login(msg['From'], password)
server.sendmail(msg['From'], msg['To'], msg.as_string())
server.quit()

With my code you can send email attachments using gmail you will need to:

Set your gmail address at ___YOUR SMTP EMAIL HERE___
Set your gmail account password at __YOUR SMTP PASSWORD HERE___
In the ___EMAIL TO RECEIVE THE MESSAGE__ part you need to set the destination email address.
Alarm notification is the subject.
Someone has entered the room, picture attached is the body.
["/home/pi/webcam.jpg"] is an image attachment.

Here is the full code:

#!/usr/bin/env python
import smtplib
from email.MIMEMultipart import MIMEMultipart
from email.MIMEBase import MIMEBase
from email.MIMEText import MIMEText
from email.Utils import COMMASPACE, formatdate
from email import Encoders
import os

USERNAME = "___YOUR SMTP EMAIL HERE___"
PASSWORD = "__YOUR SMTP PASSWORD HERE___"

def sendMail(to, subject, text, files=[]):
    assert type(to)==list
    assert type(files)==list

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

    msg.attach( MIMEText(text) )

    for file in files:
        part = MIMEBase('application', "octet-stream")
        part.set_payload( open(file,"rb").read() )
        Encoders.encode_base64(part)
        part.add_header('Content-Disposition', 'attachment; filename="%s"'
                       % os.path.basename(file))
        msg.attach(part)

    server = smtplib.SMTP('smtp.gmail.com:587')
    server.ehlo_or_helo_if_needed()
    server.starttls()
    server.ehlo_or_helo_if_needed()
    server.login(USERNAME,PASSWORD)
    server.sendmail(USERNAME, to, msg.as_string())
    server.quit()

sendMail( ["___EMAIL TO RECEIVE THE MESSAGE__"],
        "Alarm notification",
        "Someone has entered the room, picture attached",
        ["/home/pi/webcam.jpg"] )

You can also specify the type of attachment you want in your e-mail, as an example I used pdf:

def send_email_pdf_figs(path_to_pdf, subject, message, destination, password_path=None):
    ## credits: http://linuxcursor.com/python-programming/06-how-to-send-pdf-ppt-attachment-with-html-body-in-python-script
    from socket import gethostname
    #import email
    from email.mime.application import MIMEApplication
    from email.mime.multipart import MIMEMultipart
    from email.mime.text import MIMEText
    import smtplib
    import json

    server = smtplib.SMTP('smtp.gmail.com', 587)
    server.starttls()
    with open(password_path) as f:
        config = json.load(f)
        server.login('[email protected]', config['password'])
        # Craft message (obj)
        msg = MIMEMultipart()

        message = f'{message}nSend from Hostname: {gethostname()}'
        msg['Subject'] = subject
        msg['From'] = '[email protected]'
        msg['To'] = destination
        # Insert the text to the msg going by e-mail
        msg.attach(MIMEText(message, "plain"))
        # Attach the pdf to the msg going by e-mail
        with open(path_to_pdf, "rb") as f:
            #attach = email.mime.application.MIMEApplication(f.read(),_subtype="pdf")
            attach = MIMEApplication(f.read(),_subtype="pdf")
        attach.add_header('Content-Disposition','attachment',filename=str(path_to_pdf))
        msg.attach(attach)
        # send msg
        server.send_message(msg)

inspirations/credits to: http://linuxcursor.com/python-programming/06-how-to-send-pdf-ppt-attachment-with-html-body-in-python-script

None of the currently given answers here will work correctly with non-ASCII symbols in filenames with clients like GMail, Outlook 2016, and others that don’t support RFC 2231 (e.g., see here). The Python 3 code below is adapted from some other stackoverflow answers (sorry, didn’t save the origin links) and odoo/openerp code for Python 2.7 (see ir_mail_server.py). It works correctly with GMail and others, and also uses 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 = '<[email protected]>'
sender_password = '<PASSWORD>'
receiver_emails = ['<[email protected]>', '<[email protected]>']
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())

Try This i hope this might help

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 = "youremailhere"
toaddr = input("Enter The Email Adress You want to send to: ")
   
# instance of MIMEMultipart
msg = MIMEMultipart()
  
# storing the senders email address  
msg['From'] = fromaddr
  
# storing the receivers email address 
msg['To'] = toaddr
  
# storing the subject 
msg['Subject'] = input("What is the Subject:t")
# string to store the body of the mail
body = input("What is the body:t")
  
# attach the body with the msg instance
msg.attach(MIMEText(body, 'plain'))
  
# open the file to be sent 
filename = input("filename:")
attachment = open(filename, "rb")
  
# instance of MIMEBase and named as p
p = MIMEBase('application', 'octet-stream')
  
# To change the payload into encoded form
p.set_payload((attachment).read())
  
# encode into base64
encoders.encode_base64(p)
   
p.add_header('Content-Disposition', "attachment; filename= %s" % filename)
  
# attach the instance 'p' to instance 'msg'
msg.attach(p)
  
# creates SMTP session
s = smtplib.SMTP('smtp.gmail.com', 587)
  
# start TLS for security
s.starttls()
  
# Authentication
s.login(fromaddr, "yourpaswordhere)
  
# Converts the Multipart msg into a string
text = msg.as_string()
  
# sending the mail
s.sendmail(fromaddr, toaddr, text)
  
# terminating the session
s.quit()

Had a bit of a hussle in getting my script to send generic attachments but after a bit of work doing research and skimming through articles on this post, I finally came up with the following

# to query:
import sys
import ast
from datetime import datetime

import smtplib
import mimetypes
from email.mime.application import MIMEApplication
from email.mime.multipart import MIMEMultipart
from email import encoders
from email.message import Message
from email.mime.audio import MIMEAudio
from email.mime.base import MIMEBase
from email.mime.image import MIMEImage
from email.mime.text import MIMEText

from dotenv import load_dotenv, dotenv_values

load_dotenv()  # load environment variables from .env

'''
sample .env file
# .env file
SECRET_KEY="gnhfpsjxxxxxxxx"
DOMAIN="GMAIL"
TOP_LEVEL_DOMAIN="COM"
EMAIL="CHESERExxxxxx@${DOMAIN}.${TOP_LEVEL_DOMAIN}"
TO_ADDRESS = ("[email protected]","[email protected]")#didn't use this in the code but you can load recipients from here
'''

import smtplib

tls_port = 587
ssl_port = 465
smtp_server_domain_names = {'GMAIL': ('smtp.gmail.com', tls_port, ssl_port),
                            'OUTLOOK': ('smtp-mail.outlook.com', tls_port, ssl_port),
                            'YAHOO': ('smtp.mail.yahoo.com', tls_port, ssl_port),
                            'AT&T': ('smtp.mail.att.net', tls_port, ssl_port),
                            }


# todo: Ability to choose mail server provider
# auto read in from the dictionary the respective mail server address and the tls and ssl ports

class Bimail:
    def __init__(self, subject, recipients):
        self.subject = subject
        self.recipients = recipients
        self.htmlbody = ''
        self.mail_username = 'will be loaded from .env file'
        self.mail_password = 'loaded from .env file as well'
        self.attachments = []

    # Creating an smtp object
    # todo: if gmail passed in use gmail's dictionary values

    def setup_mail_client(self, domain_key_to_use="GMAIL",
                          email_servers_domains_dict=smtp_server_domain_names):
        """

        :param report_pdf:
        :type to_address: str
        """
        smtpObj = None
        encryption_status = True
        config = dotenv_values(".env")
        # check if the domain_key exists from within the available email-servers-domains dict file passed in
        # else throw an error

        # read environment file to get the Domain to be used
        if f"{domain_key_to_use}" in email_servers_domains_dict.keys():
            # if the key is found do the following
            # 1.extract the domain,tls,ssl ports from email_servers dict for use in program
            try:
                values_tuple = email_servers_domains_dict.get(f"{domain_key_to_use}")
                ssl_port = values_tuple[2]
                tls_port = values_tuple[1]
                smtp_server = values_tuple[0]

                smtpObj = smtplib.SMTP(smtp_server, tls_port)
                print(f"Success connect with tls on {tls_port}")
                print('Awaiting for connection encryption via startttls()')
                encryption_status = False

            except:
                print(f"Failed connection via tls on port {tls_port}")
                try:
                    smtpObj = smtplib.SMTP_SSL(smtp_server, ssl_port)
                    print(f"Success connect with ssl on {ssl_port}")
                    encryption_status = True
                except:
                    print(f"Failed connection via ssl on port {ssl_port}")
            finally:
                print("Within Finally block")
                if not smtpObj:
                    print("Failed!!!  no Internet connection")
                else:
                    # if connection channel is unencrypted via the use of tls encrypt it
                    if not encryption_status:
                        status = smtpObj.starttls()
                        if status[0] == 220:
                            print("Successfully Encrypted tls channel")

                    print("Successfully Connected!!!! Requesting Login")
                    # Loading .env file values to config variable
                    #load Login Creds from ENV File
                    self.mail_username = f'{config.get("EMAIL")}'
                    self.mail_password = f'{cofig.get("SECRET_KEY")}'


                    status = smtpObj.login(self.mail_usernam,self.mail_password) 

                    if status[0] == 235:
                        print("Successfully Authenticated User to xxx account")
                        success = self.send(smtpObj, f'{config.get("EMAIL")}')
                        if not bool(success):
                            print(f"Success in Sending Mail to  {success}")
                            print("Disconnecting from Server INstance")
                            quit_result = smtpObj.quit()

                        else:
                            print(f"Failed to Post {success}!!!")
                            print(f"Quiting anyway !!!")
                            quit_result = smtpObj.quit()
                    else:
                        print("Application Specific Password is Required")
        else:

            print("World")

    def send(self,smtpObj,from_address):
        msg = MIMEMultipart('alternative')
        msg['From'] = from_address
        msg['Subject'] = self.subject
        msg['To'] = ", ".join(self.recipients)  # to must be array of the form ['[email protected]']
        msg.preamble = "preamble goes here"
        # check if there are attachments if yes, add them
        if self.attachments:
            self.attach(msg)
        # add html body after attachments
        msg.attach(MIMEText(self.htmlbody, 'html'))
        # send
        print(f"Attempting Email send to the following addresses {self.recipients}")
        result = smtpObj.sendmail(from_address, self.recipients,msg.as_string())
        return result
        

    def htmladd(self, html):
        self.htmlbody = self.htmlbody + '<p></p>' + html

    def attach(self, msg):
        for f in self.attachments:

            ctype, encoding = mimetypes.guess_type(f)
            if ctype is None or encoding is not None:
                ctype = "application/octet-stream"

            maintype, subtype = ctype.split("/", 1)

            if maintype == "text":
                fp = open(f)
                # Note: we should handle calculating the charset
                attachment = MIMEText(fp.read(), _subtype=subtype)
                fp.close()
            elif maintype == "image":
                fp = open(f, "rb")
                attachment = MIMEImage(fp.read(), _subtype=subtype)
                fp.close()

            elif maintype == "ppt":
                fp = open(f, "rb")
                attachment = MIMEApplication(fp.read(), _subtype=subtype)
                fp.close()

            elif maintype == "audio":
                fp = open(f, "rb")
                attachment = MIMEAudio(fp.read(), _subtype=subtype)
                fp.close()
            else:
                fp = open(f, "rb")
                attachment = MIMEBase(maintype, subtype)
                attachment.set_payload(fp.read())
                fp.close()
                encoders.encode_base64(attachment)
            attachment.add_header("Content-Disposition", "attachment", filename=f)
            attachment.add_header('Content-ID', '<{}>'.format(f))
            msg.attach(attachment)

    def addattach(self, files):
        self.attachments = self.attachments + files


# example below
if __name__ == '__main__':
    # subject and recipients
    mymail = Bimail('Sales email ' + datetime.now().strftime('%Y/%m/%d'),
                    ['[email protected]', '[email protected]'])
    # start html body. Here we add a greeting.
    mymail.htmladd('Good morning, find the daily summary below.')
    # Further things added to body are separated by a paragraph, so you do not need to worry about newlines for new sentences
    # here we add a line of text and an html table previously stored in the variable
    mymail.htmladd('Daily sales')
    mymail.addattach(['htmlsalestable.xlsx'])
    # another table name + table
    mymail.htmladd('Daily bestsellers')
    mymail.addattach(['htmlbestsellertable.xlsx'])
    # add image chart title
    mymail.htmladd('Weekly sales chart')
    # attach image chart
    mymail.addattach(['saleschartweekly.png'])
    # refer to image chart in html
    mymail.htmladd('<img src="cid:saleschartweekly.png"/>')
    # attach another file
    mymail.addattach(['MailSend.py'])
    # send!
    
    mymail.setup_mail_client( domain_key_to_use="GMAIL",email_servers_domains_dict=smtp_server_domain_names)

I know this is an old question but I thought there must be an easier way of doing this than the other examples, thus I made a library that solves this cleanly without polluting your codebase. Including attachments is super easy:

from redmail import EmailSender
from pathlib import Path

# Configure an email sender
email = EmailSender(
    host="<SMTP HOST>", port=0,
    user_name="[email protected]", password="<PASSWORD>"
)

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

You may also directly attach bytes, a Pandas DataFrame (which is converted to format depending on file extension in the key), a Matplotlib Figure or a Pillow Image. The library is most likely all the features you need for an email sender (has a lot more than attachments).

To install:

pip install redmail

Use it any way you like. I also wrote extensive documentation: https://red-mail.readthedocs.io/en/latest/

Because there are many answers here for Python 3, but none which show how to use the overhauled email library from Python 3.6, here is a quick copy+paste from the current email examples documentation.
(I have abridged it somewhat to remove frills like guessing the correct MIME type.)

Modern code which targets Python >3.5 should no longer use the email.message.Message API (including the various MIMEText, MIMEMultipart, MIMEBase etc classes) or the even older mimetypes mumbo jumbo.

from email.message import EmailMessage
import smtplib

msg = EmailMessage()
msg["Subject"] = "Our family reunion"
msg["From"] = "me <[email protected]>"
msg["To"] = "recipient <[email protected]>"
# 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).

Here is an updated version for Python 3.6 and newer using the EmailMessage class of the overhauled email module in the Python standard library.

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

username = "[email protected]"
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()

You can find more examples here.