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If I have a list


how to get the List of Intervals /Ranges

result = {{1,3},{3,4},{4,5},{5,7}}
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up vote 18 down vote accepted


Partition[Sort@list, 2, 1]


{{1, 3}, {3, 4}, {4, 5}, {5, 7}}

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Beat me to it - 7 secs! Deleting mine, and +1. – Leonid Shifrin Jan 21 '12 at 9:30

Tom's answer is canonical, but you could also use:

With[{s = Sort[list]}, Transpose[{Most[s], Rest[s]}]]

which seems to be marginally faster for large lists. (In which case most of the time is spent sorting.)

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Alternatively: Composition[Transpose, Through, {Most, Rest}, Sort][list]. – J. M. Jan 22 '12 at 4:26

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