Randomly selecting elements without repetition

Question

I assigned energy values to each element in the array as per the program of Verbeia. The program looks like this

Xarray = A @@@ Tuples[Range[0, 1], 3];

energies = 
  RandomVariate[ExponentialDistribution[1.5], {Length@Xarray}];

f = {#, First@Pick[energies, Xarray, #]} &;

f@Xarray[[5]]

Now I want to randomly select let say 5 elements from this 1000 element array such that no element should repeat. Let { 89,5,79,34,900} be the set of elements I've randomly selected. Now for each element I should get the energies and coordinates automatically. Could anyone do this?

as per which program by verbeia? Have you looked at RandomSample? Also, what have you tried doing? — rm -rf, Jul 05 '12 at 13:49
Also, it's good form if you actually accept the answer that has helped you. So far you've asked 3 questions, accepted none and upvoted none. Time to read another faq I'm afraid: http://mathematica.stackexchange.com/faq#howtoask — Ajasja, Jul 05 '12 at 14:24

score 6 · Accepted Answer · answered Jul 05 '12 at 13:57

6

Use RandomSample:

f /@ RandomSample[Xarray, 5]

{{A[1, 1, 0], 0.666428},
 {A[1, 0, 0], 1.26861},
 {A[0, 0, 0], 0.643917},
 {A[0, 1, 0], 0.114058},
 {A[0, 0, 1], 0.200398}}

answered Jul 05 '12 at 13:57

Mr.Wizard

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6

sigh... just when I try to teach a man to fish :/ – rm -rf Jul 05 '12 at 14:01
10

If you light a man a fire you keep him warm for a day. If you light a man on fire you keep him warm for the rest of his life. – Mr.Wizard Jul 05 '12 at 14:04
lol 10987654321 – rm -rf Jul 05 '12 at 14:06

Randomly selecting elements without repetition

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