List manipulation question

*To*: mathgroup at smc.vnet.net*Subject*: [mg67163] List manipulation question*From*: "LectorZ" <lectorz at mail.ru>*Date*: Sun, 11 Jun 2006 02:17:33 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

Dear experts, I need to calculate distances between the elements of the following list: list={3700, 3800, 3900, 3950, 4000, 4050, 4100, 4150, 4200, 4250, 4300, 4350, 4400, 4450, 4500, 4550, 4600, 4650} with the following logic: a) If it is the first element, then take the simple difference to the next (i.e. 3800 - 3700) b) If it is the last element, then take the simple difference to the second last (i.e. 4650 -4600) c) the difference for all elements in between shoud be calculated as (next - last)/2 (i.e. (3900 - 3700)/2) This list should come out as a result: result={100,100,75,50,50,50,50,50,50,50,50,50,50,50,50,50,50,50} Thanks a lot for your help LZ

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