poros

saved = {}

def web_lookup(url):
    if url in saved:
        return saverd[url]
    page = urrlib.urlopen(url).read()
    saved[url] = page
    return page

# NEEDS TO BE A PURE FUNCTION, NO SIDE EFFECTS LIKE PRINT

poros

try:
    os.remove('somefile.tmp')
except OSError:
    pass

# note: checking if the file exists before deletion leads to a race condition

# PYTHON 3
from contextlib import suppress

poros

from multiprocessing import Pool

pool = Pool(4)
results = pool.map(urllib2.urlopen, urls)
pool.close() 
pool.join() 


# if you want threads instead of processes
from multiprocessing.dummy import Pool

poros

class DBConnection(object):
    def __init__(self, address):
        self.crappy_db = CrappyDBConnection(address)
    
    def __enter__(self):
        self.crappy_db.connect()
        return self  # what is returned here will be availabe via "as"
    
    def __exit__(self, exc_type, exc_val, exc_tb):
        if exc_type == ConnectionError:

poros

from contextlib import contextmanager

@contextmanager
def connect_to_db(address):
    db = CrappyDBConnection(address)
    try:
        yield db
    except ConnectionError:
        logging.exception('Connection dropped')
        db.cleanup('rollback')

poros

# USAGE
@track_entry_and_exit('widget loader')
def activity():
    print('Some time consuming activity goes here')
    load_widget()

with track_entry_and_exit('widget loader'):
    print('Some time consuming activity goes here')
    load_widget()

poros

@f1(arg)
@f2
def func(): pass
# is equivalent to
def func(): pass
func = f1(arg)(f2(func))


def my_decorator(a_function_to_decorate):
    

poros

class RoutingTable(object):
    def __init__(self, crappy_rt):
        self.crappy_rt = crappy_rt
    
    def __len__(self):
        return self.crappy_rt.getSize()
    
    def __getitem__(self, index):
        if index >= len(self):
            raise IndexError

poros

from itertools import product

 product(('ENDPOINT1', 'ENDPOINT2'), ('GET', 'POST'), ('200', '404', '500'))
 
 # returns a generator
 [('ENDPOINT1', 'GET', '200'), ('ENDPOINT1', 'GET', '404'), ('ENDPOINT1', 'GET', '500'), ('ENDPOINT1', 'POST', '200'), ('ENDPOINT1', 'POST', '404'), ('ENDPOINT1', 'POST', '500'), ('ENDPOINT2', 'GET', '200'), ('ENDPOINT2', 'GET', '404'), ('ENDPOINT2', 'GET', '500'), ('ENDPOINT2', 'POST', '200'), ('ENDPOINT2', 'POST', '404'), ('ENDPOINT2', 'POST', '500')]

poros

from collection import Counter
from collection import OrderedDict

Counter('luppolo')
Counter({'p': 2, 'l': 2, 'o': 2, 'u': 1})
help(Counter)
 |  Method resolution order:
 |      Counter
 |      __builtin__.dict
 |      __builtin__.object