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I receive as input a list of strings and need to return a list with these same strings but in randomized order. I must allow for duplicates - same string may appear once or more in the input and must appear the same number of times in the output.

I see several "brute force" ways of doing that (using loops, god forbid), one of which I'm currently using. However, knowing Python there's probably a cool one-liner do get the job done, right?

Roee Adler
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6 Answers6

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>>> import random
>>> x = [1, 2, 3, 4, 3, 4]
>>> random.shuffle(x)
>>> x
[4, 4, 3, 1, 2, 3]
>>> random.shuffle(x)
>>> x
[3, 4, 2, 1, 3, 4]
John Kugelman
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    random.shuffle(range(5)) .. does not seem to work with on the fly generated list :( – sten Apr 25 '14 at 19:08
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    @user1019129 `random.shuffle` shuffles lists in place. In Python 3, `range(5)` is a generator, not a list. In Python 2, `range(5)` is a list, but the shuffle is in place, so it shuffles a temporary list which is immediately thrown away. You can do `x = range(5); random.shuffle(x)` and then use `x`. – John Kugelman Apr 25 '14 at 20:35
13

Looks like this is the simplest way, if not the most truly random (this question more fully explains the limitations): http://docs.python.org/library/random.html#random.shuffle

Richard
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Tyler
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7

Given a string item, here is a one-liner: 

''.join([str(w) for w in random.sample(item, len(item))])
marr75
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Yann VR
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3

You'll have to read the strings into an array and then use a shuffling algorithm. I recommend Fisher-Yates shuffle

Charles Ma
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    Based on a glance at the Wikipedia article, it looks like that's more or less what it's doing anyway. You can read the code in C:\Python26\Lib\random.py (or equivalent for other OS's) and it looks like it's doing the same thing described here: http://en.wikipedia.org/wiki/Fisher%E2%80%93Yates_shuffle#Modern_method – Tyler Jun 20 '09 at 18:26
1

In python 3.8 you can use the walrus to help cram it into a couple of lines First you have to create a list from the string and store it into a variable. Then you can use random to shuffle it. Then just join the list back into a string.

random.shuffle(x := list("abcdefghijklmnopqrstuvwxyz"))
x = "".join(x)
Mikeologist
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0
import random

b = []
a = int(input(print("How many items you want to shuffle? ")))
for i in range(0, a):
    n = input('Please enter a item: ')
    b.append(n)

random.shuffle(b)

print(b)
hotfix
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inti pires
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