"""Queue represented by a Python list"""
from collections.abc import Iterable
from typing import Generic, TypeVar
_T = TypeVar("_T")
class QueueByList(Generic[_T]):
def __init__(self, iterable: Iterable[_T] | None = None) -> None:
"""
>>> QueueByList()
Queue(())
>>> QueueByList([10, 20, 30])
Queue((10, 20, 30))
>>> QueueByList((i**2 for i in range(1, 4)))
Queue((1, 4, 9))
"""
self.entries: list[_T] = list(iterable or [])
def __len__(self) -> int:
"""
>>> len(QueueByList())
0
>>> from string import ascii_lowercase
>>> len(QueueByList(ascii_lowercase))
26
>>> queue = QueueByList()
>>> for i in range(1, 11):
... queue.put(i)
>>> len(queue)
10
>>> for i in range(2):
... queue.get()
1
2
>>> len(queue)
8
"""
return len(self.entries)
def __repr__(self) -> str:
"""
>>> queue = QueueByList()
>>> queue
Queue(())
>>> str(queue)
'Queue(())'
>>> queue.put(10)
>>> queue
Queue((10,))
>>> queue.put(20)
>>> queue.put(30)
>>> queue
Queue((10, 20, 30))
"""
return f"Queue({tuple(self.entries)})"
def put(self, item: _T) -> None:
"""Put `item` to the Queue
>>> queue = QueueByList()
>>> queue.put(10)
>>> queue.put(20)
>>> len(queue)
2
>>> queue
Queue((10, 20))
"""
self.entries.append(item)
def get(self) -> _T:
"""
Get `item` from the Queue
>>> queue = QueueByList((10, 20, 30))
>>> queue.get()
10
>>> queue.put(40)
>>> queue.get()
20
>>> queue.get()
30
>>> len(queue)
1
>>> queue.get()
40
>>> queue.get()
Traceback (most recent call last):
...
IndexError: Queue is empty
"""
if not self.entries:
raise IndexError("Queue is empty")
return self.entries.pop(0)
def rotate(self, rotation: int) -> None:
"""Rotate the items of the Queue `rotation` times
>>> queue = QueueByList([10, 20, 30, 40])
>>> queue
Queue((10, 20, 30, 40))
>>> queue.rotate(1)
>>> queue
Queue((20, 30, 40, 10))
>>> queue.rotate(2)
>>> queue
Queue((40, 10, 20, 30))
"""
put = self.entries.append
get = self.entries.pop
for _ in range(rotation):
put(get(0))
def get_front(self) -> _T:
"""Get the front item from the Queue
>>> queue = QueueByList((10, 20, 30))
>>> queue.get_front()
10
>>> queue
Queue((10, 20, 30))
>>> queue.get()
10
>>> queue.get_front()
20
"""
return self.entries[0]
if __name__ == "__main__":
from doctest import testmod
testmod()