# Convert Priority Queue to List & Vice Versa in Python (Examples)

Hi! This tutorial will show you how to turn a priority queue to a list and vice-versa in the Python programming language.

First, though, here is a quick overview:

Let’s dive into Python code!

## Create Sample Priority Queue

Here, we will create the sample priority queue that will be turned into a list in this tutorial. Therefore, in your Python IDE, run the lines of code below to create the sample priority queue:

```my_tuple = ((1, "bread"), (3, "pizza"), (5, "steak"), (2, "apple"),(4, "milk"))
my_queue = sorted(my_tuple,reverse=True)

print(my_queue)

# [(5, 'steak'), (4, 'milk'), (3, 'pizza'), (2, 'apple'), (1, 'bread')]```

The program has sorted the tuples in the order of priority.

## Example 1: Queue to List | Turn Queue to List Using For Loop

In this first example, we will use a nested for loop to turn the queue into a list:

```my_list = []
for i in my_queue:
for j in i:
my_list.append(j)

print(my_list)

# [5, 'steak', 4, 'milk', 3, 'pizza', 2, 'apple', 1, 'bread']

print(type(my_list))

# <class 'list'>```

Using a nested for loop, we are able to iterate through the queue and return all its elements appended to my_list. The type() function shows that my_list has the list data type as expected.

## Example 2: Queue to List | Turn Queue to List Using List Comprehension

In this second example, we will use list comprehension to transform the queue to a list:

```my_list = [j for i in my_queue for j in i]
print(my_list)

# [5, 'steak', 4, 'milk', 3, 'pizza', 2, 'apple', 1, 'bread']

print(type(my_list))

# <class 'list'>```

The list comprehension method does exactly the same thing as the nested for loop method in the previous example, only that it is a more concise approach.

Now that we have examined how to turn a priority queue into a list, let us now consider an example of how to turn the list back into a queue.

## Example: List to Queue | Turn List to Queue Using deque() Function

One of the quickest ways to turn a list into a priority queue is to use the `deque()` function from the collections module along with a for loop like so:

```from collections import deque

# initialize a queue
queue = deque()

# loop through list and append to queue
for i in my_list:
queue.append(i)

print(queue)

# deque([5, 'steak', 4, 'milk', 3, 'pizza', 2, 'apple', 1, 'bread'])

print(type(queue))

# <class 'collections.deque'>```

The first thing is to initialize a queue. After the queue has been initialized, we then loop through the list and append its elements to the queue. Printing out the `type()` shows that it has been turned into a priority queue.

With that, we have demonstrated how to convert a priority queue to a list and vice-versa in Python. I hope you found this tutorial helpful!

## Video, Further Resources & Summary

Do you need more explanations on how to convert a priority queue to a list and vice-versa in Python? Then you should have a look at the following YouTube video of the Statistics Globe YouTube channel.

In the video, we explain in some more detail how to convert a priority queue to a list and vice-versa in Python.

Furthermore, I encourage you to check out other interesting Python list tutorials on Statistics Globe, starting with these ones:

This post has shown how to convert a priority queue to a list and vice-versa in Python. In case you have further questions, you may leave a comment below.

This page was created in collaboration with Ifeanyi Idiaye. You might check out Ifeanyi’s personal author page to read more about his academic background and the other articles he has written for the Statistics Globe website.

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