generating multiple 1-d arrays from randomizing an array

Question

I have an array of values

d = [1,2,3,4,.....100]

I am wondering how could I create several 1-D arrays (3,20 or 100) using

random.shuffle(d)

in a single loop?

Sorry, what kind of output do you expect? Different length randomized subsets from the input list, where the lengths are known up front? I think you want one list 3 with 3 random elements, one with 20 and one with 100, correct? — Martijn Pieters
– Martijn Pieters, Commented May 2, 2013 at 17:06
You could create an array to store the generated arrays. You would just append the newly generated array to the array holder. — Evo510
– Evo510, Commented May 2, 2013 at 17:08

Elias Zamaria · Accepted Answer · 2013-05-02 17:09:06Z

1

import copy, random

result = []
d = range(1, 101)
for i in xrange(100):
    result.append(copy.copy(d))
    random.shuffle(result[-1])

answered May 2, 2013 at 17:09

Elias Zamaria

102k34 gold badges122 silver badges152 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Martijn Pieters Over a year ago

You can use d[:] to create a shallow copy too, or use list(d). Shuffling a copy like that is comparable in speed to using sample(d); both create a copy and shuffle that copy.

Martijn Pieters · Accepted Answer · 2013-05-02 17:09:07Z

Use random.sample() instead, specifying a size:

sizes = (3, 20, 100)

random_lists = [random.sample(d, size) for size in sizes]

Now random_lists contains 3 randomized lists, picked from d, with 3, 20 and 100 elements respectively.

If you need a number of shuffled lists with the same length and elements as d, use random.sample() still:

random_lists = [random.sample(d, len(d)) for _ in range(3)]

Now random_lists consists of 3 lists of 100 elements, each a shuffled copy of d. From the random.sample() documentation:

Returns a new list containing elements from the population while leaving the original population unchanged. The resulting list is in selection order so that all sub-slices will also be valid random samples.

Collectives™ on Stack Overflow

generating multiple 1-d arrays from randomizing an array

2 Answers 2

1 Comment

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Related