callbacks = [lambda: print(i) for i in range(3)]

for f in callbacks:
    f()

callbacks = [lambda i=i: print(i) for i in range(3)]
for f in callbacks:
    f()  # 0 1 2

def make_printer(i):
    def _f():
        print(i)
    return _f

callbacks = [make_printer(i) for i in range(3)]
for f in callbacks:
    f()  # 0 1 2

from functools import partial

callbacks = [partial(print, i) for i in range(3)]
for f in callbacks:
    f()  # 0 1 2

import threading

for i in range(3):
    # ПЛОХО: замкнёт одно и то же i
    # threading.Timer(1, lambda: print(i)).start()

    # ХОРОШО: привяжем значение сразу
    threading.Timer(1, lambda i=i: print(i)).start()

import os
import urllib.request

from concurrent.futures import ThreadPoolExecutor, as_completed

def downloader(url):
    """Скачивает указанный URL и сохраняет его на диск"""
    req = urllib.request.urlopen(url)
    filename = os.path.basename(url)
    ext = os.path.splitext(url)[1]
    if not ext:
        raise RuntimeError('URL не содержит расширения')

    with open(filename, 'wb') as file_handle:
        while True:
            chunk = req.read(1024)
            if not chunk:
                break
            file_handle.write(chunk)

    return f'Загрузка завершена: {filename}'

def main(urls):
    """Создаёт пул потоков и скачивает указанные файлы"""
    with ThreadPoolExecutor(max_workers=5) as executor:
        futures = [executor.submit(downloader, url) for url in urls]
        for future in as_completed(futures):
            print(future.result())

if __name__ == '__main__':
    urls = [
        "https://www.irs.gov/pub/irs-pdf/f1040.pdf",
        "https://www.irs.gov/pub/irs-pdf/f1040a.pdf",
        "https://www.irs.gov/pub/irs-pdf/f1040ez.pdf",
        "https://www.irs.gov/pub/irs-pdf/f1040es.pdf",
        "https://www.irs.gov/pub/irs-pdf/f1040sb.pdf"
    ]
    main(urls)

import json

data = '{"name": "Alice", "age": 25}'
parsed = json.loads(data)
print(parsed["name"])  # Alice

from bs4 import BeautifulSoup

html = "<h1>Hello <b>Python</b></h1>"
soup = BeautifulSoup(html, "html.parser")
print(soup.h1.text)  # Hello Python

import argparse

parser = argparse.ArgumentParser()
parser.add_argument("--name")
args = parser.parse_args()
print(f"Hello, {args.name}")

import csv

with open("data.csv") as f:
    reader = csv.DictReader(f)
    for row in reader:
        print(row["username"], row["score"])

import re

text = "Email: [email protected]"
match = re.search(r"\w+@\w+\.\w+", text)
print(match.group())  # [email protected]

import ipaddress

# Создаём сеть
net = ipaddress.ip_network("192.168.1.0/24")

# Проверяем, входит ли IP в сеть
print(ipaddress.ip_address("192.168.1.42") in net)  # True
print(ipaddress.ip_address("10.0.0.5") in net)      # False

# Перебираем все адреса подсети
for ip in net.hosts():
    print(ip)
    break  # выведет первый адрес

# Работаем с IPv6 так же просто
ipv6 = ipaddress.ip_network("2001:db8::/32")
print(ipaddress.ip_address("2001:db8::1") in ipv6)  # True