Python

Contents

Performance analysis

Source: https://stackoverflow.com/questions/8624779/my-python-program-is-very-slow-how-can-i-speed-it-up-am-i-doing-something-wron

To run the python profiler and store the profiling information in prof.dat

python -m cProfile -o prof.dat <prog> <args>

To start the interactive “profile statistics tool” run

python -m pstats prof.dat

You probably first want to sort the results

sort time # sort by tottime, the total time spent in the function alone
sort cumtime # sort by cumtime, the total time spent in the function plus all functions that this function called

and afterwards print those

stats # print the whole statistic
stats <N> # print the first N entries

Mail via Python 

# import necessary packages
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText
from email.mime.application import MIMEApplication
import email.utils
import smtplib
import os.path

def sendMail(server, port, user, password, fromMailadress, fromName, toMailadress, toName, subject, message, attachments=[], replyToMailadress=""):
    # create message object instance
    msg = MIMEMultipart()
    # setup the parameters of the message
    msg['To'] = email.utils.formataddr((toName, toMailadress))
    msg['From'] = email.utils.formataddr((fromName, fromMailadress))
    msg['Date'] = email.utils.formatdate(localtime=True)
    msg['Subject'] = subject
    msg.add_header('reply-to', replyToMailadress)
    # add in the message body
    msg.attach(MIMEText(message, 'plain'))
    # attach files
    for filename in attachments:
        if not os.path.isfile(filename):
            continue
        with open(filename, "rb") as f:
            part = MIMEApplication(f.read(),Name=os.path.basename(filename))
            # After the file is closed
            part['Content-Disposition'] = 'attachment; filename="%s"' % os.path.basename(filename)
            msg.attach(part)
    # create server connection
    server = smtplib.SMTP(server + ": " + port)
    server.starttls()
    server.ehlo()
    # Login Credentials for sending the mail
    server.login(user, password)
    # send the message via the server.
    try:
        server.sendmail(msg['From'], msg['To'], msg.as_string())
    finally:
        server.quit()

Python-venv

Installation:

apt install python3-venv

Setup:

python3 -m venv myvenv
cd myvenv
source bin/activate
pip install -U pip

Install dependency (e.g. django)

pip install django

Install dependency with specific version

pip install django==1.10

Store dependencies

pip freeze > requirements.txt

Retrieve dependencies

pip install -r requirements.txt