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position of sequence of numbers in list


Hi,

What is the most efficient way to find the position of the beginning
of a sequence of numbers from a list?

I found a couple of ways:

find 3,4 in list={1,2,3,4,5};

 1.   pos=Intersection[Position[list,3],(Position[list,4])+1]

 2.   pos=Position[Partition[list,2,1],{3,4}]

Are there other ways to do this?
What is the best way when dealing with large lists?

Thanks,
JB


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