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Description:

prqrs 0.1.0

prqrs

Python priority queue in Rust via pyo3

The prqrs package provides a simple interface to a priority queue implemented in Rust. This
guide will show you how to create a priority queue, add items to it, and retrieve items based on
their priority.
Installation

To build the Rust project from source run:
maturin develop --release

Alternatively using the PDM package manager, just run pdm install.
Usage
Creating a Priority Queue
To create a priority queue, import the PriorityQueue class from the prqrs package and
instantiate it:
from prqrs import PriorityQueue

pq = PriorityQueue()

Creating Items
Items that can be added to the priority queue need a value and a priority.
Import the Item class and create items:
from prqrs import Item

item1 = Item(value=5, priority=3) # An item with value 5 and priority 3
item2 = Item(value=10, priority=1) # An item with value 10 and priority 1

Adding Items to the Queue
Add items to the queue using the push method:
pq.push(item1)
pq.push(item2)

Retrieving Items from the Queue
Retrieve items based on their priority using the pop method.
This method returns the item with the highest priority (lowest numerical value of priority):
highest_priority_item = pq.pop()
if highest_priority_item is not None:
print(f"Value: {highest_priority_item.value}, Priority: {highest_priority_item.priority}")

Checking if the Queue is Empty
To check whether the priority queue is empty, use the is_empty method:
if pq.is_empty():
print("The priority queue is empty.")
else:
print("The priority queue is not empty.")

Example
Here is a complete example that demonstrates creating a priority queue, adding items, and retrieving
them:
from prqrs import PriorityQueue, Item

# Create a priority queue
pq = PriorityQueue()

# Add items
pq.push(Item(value=5, priority=3))
pq.push(Item(value=10, priority=1))
pq.push(Item(value=7, priority=2))

# Retrieve and print items
while not pq.is_empty():
item = pq.pop()
print(f"Value: {item.value}, Priority: {item.priority}")

This will output
Value: 5, Priority: 3
Value: 7, Priority: 2
Value: 10, Priority: 1

Benchmarking
Running pdm install (or maturin develop) to install the Rust wheel followed by python benchmark_1m.py:
1.1 GHz CPU: (0.18+0.51)s
Enqueue time for 1 million items: 0.1798386573791504 seconds
Dequeue time for 1 million items: 0.5103330612182617 seconds

3.7 GHz CPU: (0.08+0.19)s
Enqueue time for 1 million items: 0.08250904083251953 seconds
Dequeue time for 1 million items: 0.1858220100402832 seconds