Примеры Python кода

# ПРИМЕР 1
from collections.abc import Iterator


class PrintingIterator(Iterator):
    def __init__(self, items):
        self.items = items
        self.index = 0
        print("Inited printing iterator with items", items)

    def __next__(self):
        if self.index >= len(self.items):
            print("Index out of range, stopping iteration")
            raise StopIteration

        value = self.items[self.index]
        self.index += 1
        print("* returning value", value, "from index", self.index)
        return value

# ПРИМЕР 2
class NetworkConnection:
    def __init__(self, url):
        self.url = url
        self._conn = None

    def __enter__(self):
        self._conn = object()
        print(f"Connecting to {self.url!r}, conn: {self._conn!r}")
        return self

    def __exit__(self, exc_type, exc_val, exc_tb):
        if exc_type is not None:
            print(f"got an exception {exc_type}, closing connection")

        print(f"Closing connection to {self.url!r}, conn: {self._conn!r}")


# ПРИМЕР 3
class Point:
    def __init__(self, x, y):
        self.x = x
        self.y = y

    def add(self, other):
        return self.__class__(
            self.x + other.x,
            self.y + other.y,
        )


# ПРИМЕР 4
class Point:
    def __init__(self, x, y):
        self.x = x
        self.y = y