Save multiple shuffled csv files

Question

is there a quick way to shuffle a list n times (in a different order) and save it as n single csv file? I already searched a lot, but couln't find anything about that. I have the following code, but I'm sure it could be shorter and with this I can't be sure that all shuffled lists have a different order. Has someone a solution?

import random

example = ['S01_a', 'S01_b', 'S02_a', 'S02_b', 'S03_a', 'S03_b', 'S04_a']

while True:
    example

    shuffle3 = []

    last = ""

    while example:
        i = example
        if last:
            i = [x for x in i if x[4] != last[4]]
        if not i:
            #no valid solution
            break 
        newEl = random.choice(i)
        last = newEl
        shuffle3.append(newEl)
        example.remove(newEl)
    if not example:
        break


fid = open("example.csv", encoding='latin1', mode="w")
fid.writelines(shuffle3)
fid.close()

Answer 1

You could generate all possible permutations over the list indices, then pick the elements in the order given by the permutation to generate a new shuffled list. Finally, shuffle the list of lists and pick the first N.

from itertools import permutations
from random import shuffle


example = ['S01_a', 'S01_b', 'S02_a', 'S02_b', 'S03_a', 'S03_b', 'S04_a']
indices = [x for x in range(0,len(example))]
n_perm = 5

all_permutations = list(set(permutations(indices)))
shuffle(all_permutations)
my_permutations = all_permutations[:n_perm]       

for index, elem in enumerate(my_permutations):

    new_shuffle = [example[x] for x in elem]    
    with open("example_{}.csv".format(str(index)), "w") as fid:
        fid.writelines(",".join(new_shuffle))

Answer 2

You can do:

import itertools, random
N = 5
example = ['S01_a', 'S01_b', 'S02_a', 'S02_b', 'S03_a', 'S03_b', 'S04_a']
all_options = list(itertools.permutations(example, len(example)))
my_lists = random.choices(all_options, k=N)
my_lists

Output:

[('S02_b', 'S01_a', 'S03_a', 'S01_b', 'S02_a', 'S03_b', 'S04_a'),
 ('S03_b', 'S02_b', 'S01_b', 'S03_a', 'S01_a', 'S02_a', 'S04_a'),
 ('S02_a', 'S04_a', 'S03_a', 'S02_b', 'S03_b', 'S01_b', 'S01_a'),
 ('S02_b', 'S04_a', 'S01_a', 'S02_a', 'S03_b', 'S01_b', 'S03_a'),
 ('S03_a', 'S04_a', 'S01_b', 'S02_a', 'S02_b', 'S01_a', 'S03_b')]

And then if you want to do something for each of them seperatly, just loop them:

for l in my_lists:
    I_do_what_it_want with l...

Answer 3

something like this ? you have to looking for a library to genrate csv

import java.util.*; 

public class GFG 
{ 
    public static void main(String[] args) 
    { 
        ArrayList<String>  mylist = new ArrayList<String>(); 
        mylist.add("code"); 
        mylist.add("quiz"); 
        mylist.add("geeksforgeeks"); 
        mylist.add("quiz"); 
        mylist.add("practice"); 
        mylist.add("qa"); 

        System.out.println("Original List : \n" + mylist); 

        // Here we use Random() to shuffle given list. 
        Collections.shuffle(mylist, new Random()); 
        System.out.println("\nShuffled List with Random() : \n"
                                                     + mylist); 

        // Here we use Random(3) to shuffle given list. 
        Collections.shuffle(mylist, new Random(3)); 
        System.out.println("\nShuffled List with Random(3) : \n"
                                                     + mylist); 

        // Here we use Random(3) to shuffle given list. 
        Collections.shuffle(mylist, new Random(5)); 
        System.out.println("\nShuffled List with Random(5) : \n"
                                                     + mylist); 

    } 
}