# Extracting a random sample from a list [closed]

This is sample data

data = {{1, 1, 1, 1, 1, 1}, {2, 2, 2, 2, 2, 2}, {3, 3, 3, 3, 3, 3},
{5, 5, 5, 5, 5, 5}, {6, 6, 6, 6, 6, 6}}


My actual data contains 10000 sub-lists with 6 elements.

How can I create a new list data2 containing a sample of N random six-lets of the initial list?

In our MWE let's take N = 3.

## closed as off-topic by Dr. belisarius, Michael E2, Daniel Lichtblau, dr.blochwave, user9660 Nov 26 '15 at 19:00

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• RandomSample[data, 3] I believe you have to practice your docs-fu – Dr. belisarius Nov 26 '15 at 17:47
• @belisariushassettled With your suggestion is there a chance a six-let to appear twice or more times in the new list, or all N are different? – Vaggelis_Z Nov 26 '15 at 17:52
• Dude, don't ask those things. Go to the docs and check them out – Dr. belisarius Nov 26 '15 at 17:54
• @belisariushassettled You are right! Some times I so lazy... – Vaggelis_Z Nov 26 '15 at 18:02

If I understood well, you do not want to create those sample elements out of the elements of sublists. With this assumption the answer is

n=3;
data2=RandomChoice[data, n]


Example output:

{{3, 3, 3, 3, 3, 3}, {2, 2, 2, 2, 2, 2}, {2, 2, 2, 2, 2, 2}}


If you would like to randomly select out of all elements it would be:

data2=RandomChoice[Flatten@data, {n, 6}]


Example output:

{{2, 6, 1, 5, 3, 1}, {6, 1, 5, 2, 1, 6}, {3, 3, 6, 2, 2, 1}}


EDIT: If no elements are supposed to repeat then it would be:

data2=RandomSample[data, n]


Example output:

{{2, 2, 2, 2, 2, 2}, {5, 5, 5, 5, 5, 5}, {3, 3, 3, 3, 3, 3}}

• No, I want N random six-lets from the initial data. But all of them should be different. In your suggestion the six-let (2,2,2,2,2,2) appears twice! – Vaggelis_Z Nov 26 '15 at 17:50
• The last one is really what I want! – Vaggelis_Z Nov 26 '15 at 17:55