tyong920

Database transactions

pymysql

• Defaults to autocommit=False

connection = pymysql.connect(user='user', db='test')
cursor = connection.cursor()
cursor.execute('insert into test (value) values (10)')

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import logging

logger = logging.getLogger('simple_example')
logger.setLevel(logging.DEBUG)
# create file handler that logs debug and higher level messages
fh = logging.FileHandler('spam.log')
fh.setLevel(logging.DEBUG)
# create console handler with a higher log level
ch = logging.StreamHandler()
ch.setLevel(logging.ERROR)

tyong920

from twisted.enterprise import adbapi
from twisted.python import log
import MySQLdb

class ReconnectingConnectionPool(adbapi.ConnectionPool):
    """Reconnecting adbapi connection pool for MySQL.

    This class improves on the solution posted at
    http://www.gelens.org/2008/09/12/reinitializing-twisted-connectionpool/
    by checking exceptions by error code and only disconnecting the current

tyong920

tmux shortcuts & cheatsheet

start new:

tmux

start new with session name:

tmux new -s myname

tyong920

"""
A demo of creating a new database via SQL Alchemy.

Under MIT License from sprin (https://gist.github.com/sprin/5846464/)

This module takes the form of a nosetest with three steps:
    - Set up the new database.
    - Create a table in the new database.
    - Teardown the new database.
"""

tyong920

Transforming Code into Beautiful, Idiomatic Python

Notes from Raymond Hettinger's talk at pycon US 2013 video, slides.

The code examples and direct quotes are all from Raymond's talk. I've reproduced them here for my own edification and the hopes that others will find them as handy as I have!

Looping over a range of numbers

for i in [0, 1, 2, 3, 4, 5]:

tyong920

The Best of the Best Practices (BOBP) Guide for Python

A "Best of the Best Practices" (BOBP) guide to developing in Python.

In General

Values

• "Build tools for others that you want to be built for you." - Kenneth Reitz
• "Simplicity is alway better than functionality." - Pieter Hintjens

tyong920

#!/usr/bin/env python3
'''Serving dynamic images with Pandas and matplotlib (using flask).'''

import matplotlib
matplotlib.use('Agg')

import matplotlib.pyplot as plt
import numpy as np
import pandas as pd
from io import BytesIO

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async def main():
    coroutine1 = do_some_work(1)
    coroutine2 = do_some_work(2)
    coroutine3 = do_some_work(4)

    tasks = [
        asyncio.ensure_future(coroutine1),
        asyncio.ensure_future(coroutine2),
        asyncio.ensure_future(coroutine3)
    ]

tyong920

import pandas as pd
import pymysql
from sqlalchemy import create_engine

engine = create_engine('mysql+pymysql://<user>:<password>@<host>[:<port>]/<dbname>')

df = pd.read_sql_query('SELECT * FROM table', engine)
df.head()