Cara menggunakan SHUFFLE pada Python

Python: Shuffle the elements of a given list

Python | Ways to shuffle a list

Shuffling a sequence of numbers have always been an useful utility and the question that has appeared in many company placement interviews as well. Knowing more than one method to achieve this can always be a plus. Let’s discuss certain ways in which this can be achieved.
Method #1 : Fisher–Yates shuffle Algorithm
This is one of the famous algorithms that is mainly employed to shuffle a sequence of numbers in python. This algorithm just takes the higher index value, and swaps it with current value, this process repeats in a loop till end of the list.

Table of Contents

• Python: Shuffle the elements of a given list
• Python | Ways to shuffle a list
• Python Random shuffle() Method
• How to Shuffle and Return a New List?
• Where to Go From Here?
• Shuffle a list, string, tuple in Python (random.shuffle, sample)
• What is the Difference Between .shuffle and .sample?
• Shuffle a Python List and Re-assign It to Itself
• Write a Python program to shuffle all the elements in a given series

Table of Contents

• Python: Shuffle the elements of a given list
• Python | Ways to shuffle a list
• Python Random shuffle() Method
• How to Shuffle and Return a New List?
• Where to Go From Here?
• Shuffle a list, string, tuple in Python (random.shuffle, sample)
• What is the Difference Between .shuffle and .sample?
• Shuffle a Python List and Re-assign It to Itself
• Write a Python program to shuffle all the elements in a given series

Python3

# Python3 code to demonstrate

# shuffle a list

# using Fisher–Yates shuffle Algorithm

import random

# initializing list

test_list = [1, 4, 5, 6, 3]

# Printing original list

print ("The original list is : " + str(test_list))

# using Fisher–Yates shuffle Algorithm

# to shuffle a list

for i in range(len(test_list)-1, 0, -1):

# Pick a random index from 0 to i

j = random.randint(0, i + 1)

# Swap arr[i] with the element at random index

test_list[i], test_list[j] = test_list[j], test_list[i]

# Printing shuffled list

print ("The shuffled list is : " + str(test_list))

Output: The original list is : [1, 4, 5, 6, 3] The shuffled list is : [4, 3, 1, 5, 6]

Method #2 : Using random.shuffle()
This is most recommended method to shuffle a list. Python in its random library provides this inbuilt function which in-place shuffles the list. Drawback of this is that list ordering is lost in this process. Useful for developers who choose to save time and hustle.

Python3

# Python3 code to demonstrate

# shuffle a list

# using random.shuffle()

import random

# initializing list

test_list = [1, 4, 5, 6, 3]

# Printing original list

print ("The original list is : " + str(test_list))

# using random.shuffle()

# to shuffle a list

random.shuffle(test_list)

# Printing shuffled list

print ("The shuffled list is : " + str(test_list))

Output: The original list is : [1, 4, 5, 6, 3] The shuffled list is : [5, 6, 4, 3, 1]

Method #3 : Using random.sample()
This is quite a useful function, better than the shuffle method used above in aspect that it creates a new shuffled list and returns it rather than disturbing the order of original list. This is useful in cases we require to retain the original list.

Python3

# Python3 code to demonstrate

# shuffle a list

# using random.sample()

import random

# initializing list

test_list = [1, 4, 5, 6, 3]

# Printing original list

print ("The original list is : " + str(test_list))

# using random.sample()

# to shuffle a list

res = random.sample(test_list, len(test_list))

# Printing shuffled list

print ("The shuffled list is : " + str(res))

Output: The original list is : [1, 4, 5, 6, 3] The shuffled list is : [5, 3, 6, 1, 4]

Method 4:

In this method we select a index randomly and append that element at that index to the list.

Python3

import random

# Assign array

arr = [1, 2, 3, 4, 5, 6]

# Display original array

print("Original List: ", arr)

# Get length of List

n = len(arr)

#repeat the following for n number of times

for i in range(n):

#select an index randomly

j = random.randint(0, n-1)

#delete the element at that index.

element=arr.pop(j)

#now append that deleted element to the list

arr.append(element)

print("Shuffled List: ",arr)

Output Original List: [1, 2, 3, 4, 5, 6] Shuffled List: [4, 5, 3, 2, 6, 1]

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Python Random shuffle() Method

❮ Random Methods

Example

Shuffle a list (reorganize the order of the list items):

import random

mylist = ["apple", "banana", "cherry"]
random.shuffle(mylist)

print(mylist)

Try it Yourself »

How to Shuffle and Return a New List?

The default random.shuffle(a) method modifies an existing list a. It works in-place. So, what if you want to shuffle the original list but return a new list while leaving the original list elements unchanged?

No problem—use slicing to copy the list.

Exercise: Take a guess—what’s the output of this code snippet? You can check your guess in our interactive code shell:

Related articles:

• How to copy a list?
• Slicing
• Python Lists [Ultimate Guide]
• The random module explained

Where to Go From Here?

Enough theory. Let’s get some practice!

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You build high-value coding skills by working on practical coding projects!

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If your answer is YES!, consider becoming a Python freelance developer! It’s the best way of approaching the task of improving your Python skills—even if you are a complete beginner.

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To help students reach higher levels of Python success, he founded the programming education website Finxter.com. He’s author of the popular programming book Python One-Liners (NoStarch 2020), coauthor of the Coffee Break Python series of self-published books, computer science enthusiast, freelancer, and owner of one of the top 10 largest Python blogs worldwide.

His passions are writing, reading, and coding. But his greatest passion is to serve aspiring coders through Finxter and help them to boost their skills. You can join his free email academy here.

Shuffle a list, string, tuple in Python (random.shuffle, sample)

Posted: 2020-02-05 / Tags: Python, List

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To randomly shuffle elements of lists (list), strings (str), and tuples (tuple) in Python, use the random module.

• random — Generate pseudo-random numbers — Python 3.8.1 documentation

random provides shuffle() that shuffles the original list in place, and sample() that returns a new list that is randomly shuffled. sample() can also be used for strings and tuples.

• random.shuffle() shuffles the original list
• random.sample() returns a new shuffled list
• Shuffle strings and tuples
• Initialize the random number generator with random.seed()

If you want to sort in ascending or descending order or reverse instead of shuffling, see the following articles.

• Sort a list, string, tuple in Python (sort, sorted)
• Reverse a list, string, tuple in Python (reverse, reversed)

What is the Difference Between .shuffle and .sample?

Python comes built-in with an incredibly helpful library to generate randomness, called random. Throughout this tutorial, you’ll learn how to use the random.shuffle() and random.sample() functions. Before we dive into how to use them, however, let’s quickly explore what the differences are.

Both functions return a list that is randomly sorted, but how they return them is different:

• random.shuffle() shuffles the original list, meaning the shuffling can be done in-place
• random.sample() returns a new shuffled list, based on the original list

random.sample() can also be used to shuffle strings and tuples, as it creates a new list, thereby allowing you to work on immutable data types.

Now, let’s dive into how to shuffle a list in Python!

Check out some other Python tutorials on datagy, including our complete guide to styling Pandas and our comprehensive overview of Pivot Tables in Pandas!

Shuffle a Python List and Re-assign It to Itself

The random.shuffle() function makes it easy to shuffle a list’s items in Python. Because the function works in-place, we do not need to reassign the list to itself, but it allows us to easily randomize list elements.

Let’s take a look at what this looks like:

# Shuffle a list using random.shuffle() import random a_list = ['welcome', 'to', 'datagy', 'where', 'you', 'will', 'learn', 'Python', 'and', 'more'] random.shuffle(a_list) print(a_list) # Returns: ['more', 'will', 'Python', 'welcome', 'learn', 'you', 'where', 'to', 'datagy', 'and']

What we’ve done here is:

1. Create a new list
2. Applied the random.shuffle() function to it
3. Printed the result to verify the shuffling

Keep in mind, if you’re following along with the example above, your randomly sorted list will probably look different!

In the next section, you’ll learn how to use the random.sample() function to randomize a list in Python.

Want to learn more about Python list comprehensions? Check out this in-depth tutorial that covers off everything you need to know, with hands-on examples. More of a visual learner, check out my YouTube tutorial here.

Write a Python program to shuffle all the elements in a given series

PythonPandasServer Side ProgrammingProgramming

Assume, you have a dataframe and the result for shuffling all the data in a series,

The original series is 0 1 1 2 2 3 3 4 4 5 dtype: int64 The shuffled series is : 0 2 1 1 2 3 3 5 4 4 dtype: int64