Enhance the implementation of Queue using list (#8608)

* enhance the implementation of queue using list

* enhance readability of queue_on_list.py

* rename 'queue_on_list' to 'queue_by_list' to match the class name

data_structures/queue/queue_by_list.py

@@ -0,0 +1,141 @@
+"""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()

data_structures/queue/queue_on_list.py

@@ -1,52 +0,0 @@
-"""Queue represented by a Python list"""
-
-
-class Queue:
-    def __init__(self):
-        self.entries = []
-        self.length = 0
-        self.front = 0
-
-    def __str__(self):
-        printed = "<" + str(self.entries)[1:-1] + ">"
-        return printed
-
-    """Enqueues {@code item}
-    @param item
-        item to enqueue"""
-
-    def put(self, item):
-        self.entries.append(item)
-        self.length = self.length + 1
-
-    """Dequeues {@code item}
-    @requirement: |self.length| > 0
-    @return dequeued
-        item that was dequeued"""
-
-    def get(self):
-        self.length = self.length - 1
-        dequeued = self.entries[self.front]
-        # self.front-=1
-        # self.entries = self.entries[self.front:]
-        self.entries = self.entries[1:]
-        return dequeued
-
-    """Rotates the queue {@code rotation} times
-    @param rotation
-        number of times to rotate queue"""
-
-    def rotate(self, rotation):
-        for _ in range(rotation):
-            self.put(self.get())
-
-    """Enqueues {@code item}
-    @return item at front of self.entries"""
-
-    def get_front(self):
-        return self.entries[0]
-
-    """Returns the length of this.entries"""
-
-    def size(self):
-        return self.length