Python3 Snippets

Python3_Snippets.py

# Quick Virtualenv


sudo apt-get install python3-pip python3-virtualenv
virtualenv .venv && source .venv/bin/activate
which pip # .venv/bin/pip
pip install -r requirements

# CSV


## To and from list of dictionaries

import csv

with open('df_big.csv') as f:
    reader = csv.DictReader(f)
    list_of_dicts = list(reader)

with open('output.csv', 'w') as f:
    writer = csv.DictWriter(f, list_of_dicts[0].keys())
    writer.writeheader()
    writer.writerows(list_of_dicts)

# Logging 

## Shorthand

import logging, logging.handlers

logging.basicConfig(
    level=logging.DEBUG,
    format="%(asctime)s [%(levelname)s] %(message)s",
    handlers=[
        logging.handlers.RotatingFileHandler('debug.log', mode='a', maxBytes=5*1024*1024, backupCount=2),
        logging.StreamHandler() # echo to screen
    ]
)

# Glob files

import glob

def glob_files(dir_path, match='*.html'):
    return glob.glob(f'{dir_path}/{match}')

# Requests

import requests

## prep a request
request = requests.Request('POST', url, headers=headers, json=payload).prepare()
## inspect request
print( json.dumps( request.__dict__, indent=1, default=str)) )
## send request
response = session.send( request )

# Simple print in colour
# Source: https://github.com/coleifer/huey/blob/master/examples/django_ex/djangoex/test_app/tasks.py

def tprint(s, c=32):
    # Helper to print messages from within tasks using color, to make them
    # stand out in examples.
    # c = 31 -> 36
    print('\x1b[1;%sm%s\x1b[0m' % (c, s))
   

# Date range generator function

import datetime

def today_and_yesterday(today=None):
    if today is None:
        today = datetime.datetime.utcnow().replace(
            hour=0, minute=0, second=0, microsecond=0
        )
    yesterday = today - datetime.timedelta(days=1)
    return today, yesterday


def date_range_generator(starts, ends = None, step=None):
    if step is None:
        step = datetime.timedelta(days=1)
        
    if ends is None:
        _, ends = today_and_yesterday()
    
    current = starts
    while current <= ends:
        yield current
        current = current + step

        
# decorator that makes functions fail silently - use at your own risk!
def fail_silently(func):
    def wrapper(*args, **kwargs):
        try:
            return func(*args, **kwargs)
        except:
            return None
    return wrapper