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How can I select the duplicate values in a list?


{1, 2, 1, 1, 1, 1}
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marked as duplicate by Öskå, Leonid Shifrin, m_goldberg, tkott, RunnyKine Jun 9 '14 at 16:22

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

I need to return the duplicate values. – Developer2000 Jun 9 '14 at 15:07
So in your example what do you need to return? – Öskå Jun 9 '14 at 15:08
I need to return {1} – Developer2000 Jun 9 '14 at 15:15
Have you even looked at the link above? It returns {1}. Please make an effort. – Öskå Jun 9 '14 at 15:17
@Öskå, I am so sorry! thanks – Developer2000 Jun 9 '14 at 15:20

If you want all duplicates then:

list = {1, 2, 1, 1, 1, 1}

Select[Split@Sort@list, Length@# > 1 &]

if you want one from each duplicate then

Select[Split@Sort@list, Length@# > 1 &][[;;,1]]
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