vlad-bezden

from typing import Callable, Iterable, Any

def first(predicate: Callable, collection: Iterable) -> Any:
    for x in collection:
        if predicate(x): 
            return x
        
def first(predicate: Callable, collection: Iterable) -> Any:
    return next((x for x in collection if predicate(x)), None)

vlad-bezden

from typing import Iterator, Any, Iterable, TypeVar, Tuple

T_ = TypeVar('T_')
Pairs_Iter = Iterator[Tuple[T_, T_]]

def legs(iterable: Iterator[T_]) -> Pairs_Iter:
    begin = next(iterable)
    for end in iterable:
        yield begin, end
        begin = end

vlad-bezden

def transform(data):
    return [list(x) for x in zip(*data)]

data = [[*range(3)], [*range(3, 6)], [*range(6, 9)]]
# [[0, 1, 2], [3, 4, 5], [6, 7, 8]]


data_t = transform(data)
# [[0, 3, 6], [1, 4, 7], [2, 5, 8]]

vlad-bezden

def couple(iterable, *, first=None):
    """Yield each iterable item along with the item before it."""
    prev = first
    for item in iterable:
        yield prev, item
        prev = item

# >>> list(couple(range(5)))
# >>> [(None, 0), (0, 1), (1, 2), (2, 3), (3, 4)]
# >>> list(couple(range(5), first=10))

vlad-bezden

from contextlib import contextmanager
import time

@contextmanager
def timer():
    start = time.time()
    yield
    print(f'\N{greek capital letter delta}t \N{rightwards arrow} {time.time() - start:.2f}s')

vlad-bezden

from time import time

import aiopg
import asyncio

CONN_INFO = {
    'host': 'POSTGRESQL_SERVER',
    'user': 'user_name',
    'port': 1234,
    'database': 'some_dabase',

vlad-bezden

from datetime import timedelta
from functools import reduce
from itertools import chain, repeat
from typing import List

def calc(times: List[str]) -> timedelta:
    '''Calculates total time from the list of times'''
    
    result = timedelta()
    for t in times:

vlad-bezden

import pandas_datareader as pdr
import pandas as pd
import datetime

def get(tickers, start_date, end_date=None):
    def data(ticker):
        return pdr.get_data_yahoo(ticker, start=start_date, end=end_date)

    datas = map(data, tickers)
    return(pd.concat(datas, keys=tickers, names=['Ticker', 'Date']))

vlad-bezden

import pandas_datareader as pdr
import datetime

aapl = pdr.get_data_yahoo('AAPL',
                          start=datetime.datetime(2007, 1, 1),
                          end=datetime.datetime(2018, 1, 1))

# resample 'aapl' to business months, take last observation
monthly = aapl.resample('BM').apply(lambda x: x[-1])

vlad-bezden

import pandas_datareader as web

uah = web.DataReader('UAH=X', 'yahoo', start='2017-01-01')