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File Name: queue_priority.py 

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print("""
PriorityQueue Class:
A priority queue, where elements are dequeued based on their priority. Elements must be comparable.
Example: from queue import PriorityQueue
""")

print("""
- Elements are popped from the queue based on their priority. Lower values have higher priority.
- The elements are dequeued in ascending order of priority.
- In case of ties in priority, the elements are dequeued in the order they were added.
- The elements in the priority queue are tuples, and the priority is determined by the first element of each tuple. 
- The element with the lowest value in the first position will have the highest priority
""")

print("""
PriorityQueue uses a heap data structure internally 
      to efficiently maintain the order of elements based on their priorities
""")

print("""
the ordering of strings in the PriorityQueue is based on lexicographical order,
which means it's based on the ASCII values of the characters.
The comparison is done character by character from left to right,
and the first differing character determines the order.

""")
from queue import PriorityQueue

class CustomPriorityQueue:
  def __init__(self):
    self.queue = PriorityQueue()

  def enqueue(self, item, priority):
    """Add an item to the queue with a specified priority."""
    self.queue.put((priority, item))

  def dequeue(self):
    """Remove and return the item with the highest priority from the queue."""
    if not self.is_empty():
      return self.queue.get()[1]
    else:
      print("Queue is empty")
      return None

  def is_empty(self):
    """Check if the queue is empty."""
    return self.queue.empty()

  def size(self):
    """Return the number of items in the queue."""
    return self.queue.qsize()

  def peek(self):
    """Return the item with the highest priority in the queue without removing it."""
    if not self.is_empty():
      return self.queue.queue[0][1]
    else:
      print("Queue is empty")
      return None

# Example usage:
if __name__ == "__main__":
  grocery_queue = CustomPriorityQueue()
  print("Initial queue:", list(grocery_queue.queue.queue))

  # Adding people to the queue with priorities
  grocery_queue.enqueue("Venkat", 2)
  grocery_queue.enqueue("Suba", 1)
  grocery_queue.enqueue("Gutti", 3)
  print("Queue after adding people:", list(grocery_queue.queue.queue))

  # Serving people from the queue
  serving_person = grocery_queue.dequeue()
  print("Serving:", serving_person)
  print("Queue after serving:", list(grocery_queue.queue.queue))

  # Checking the next person to be served
  next_person = grocery_queue.peek()
  print("Next person to be served:", next_person)

Documentation

from queue import PriorityQueue

class CustomPriorityQueue: def init(self): self.queue = PriorityQueue()

def enqueue(self, item, priority): self.queue.put((priority, item))

def dequeue(self): if not self.is_empty(): return self.queue.get()[1] else: print("Queue is empty") return None

def is_empty(self): return self.queue.empty()

def size(self): return self.queue.qsize()

def peek(self): if not self.is_empty(): return self.queue.queue[0][1] else: print("Queue is empty") return None

Example usage:

if name == "main": grocery_queue = CustomPriorityQueue() print("Initial queue:", list(grocery_queue.queue.queue))

# Adding people to the queue with priorities grocery_queue.enqueue("Venkat", 2) grocery_queue.enqueue("Suba", 1) grocery_queue.enqueue("Gutti", 3) print("Queue after adding people:", list(grocery_queue.queue.queue))

# Serving people from the queue serving_person = grocery_queue.dequeue() print("Serving:", serving_person) print("Queue after serving:", list(grocery_queue.queue.queue))

# Checking the next person to be served next_person = grocery_queue.peek() print("Next person to be served:", next_person)