selecting certain values from a list

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Michael
Michael 2011-6-28
I have this list below (call it A), and i wish to find the last value of a group of numbers. if you look at the numbers, they are bunched together in groups (not always consecutively), and i only want the last number in each group.
A =
8
9
106
107
109
110
244
245
325
326
329
334
335
483
484
485
486
527
528
690
691
So the new list (call it B), should look like this..
B =
9
110
245
335
486
528
691
I was thinking of making a for loop (i=1:length(A)) and doing a 'find' to see if a number exists in between that number and +20 after it (each new group of numbers never exceeds beyond 20).
is this possible? thank you in advance

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采纳的回答

Paulo Silva
Paulo Silva 2011-6-28
M=[ 8 9 106 107 109 110 244 245 325 326 329 334 335 483 484 485 486 527 528 690 691]
d=diff(M); %find the diference between consecutive values
[M(d>1);M(end)] %get the values with diference bigger than 1
append M(end) because the last one is always the last from a group and the diference function doesn't catch it
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Sean de Wolski
Sean de Wolski 2011-6-28
OP: "I was thinking of making a for loop (i=1:length(A)) and doing a 'find' to see if a number exists in between that number and +20 after it (each new group of numbers never exceeds beyond 20)."
so basically anywhere there's a gap of more than 20 it fails.
Michael
Michael 2011-6-28
if the numbers are 398 399 400 401, then in my case they will all belong to the same group. these numbers in my case represent indices for a data set, and the gap between groups of data is usually higher than 100, and each different "cluster" of close numbers usually doesnt exceed 10, but i used 20 to be safe, with the intention of only gathering the last value of each group.

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更多回答（1 个）

Andrei Bobrov
Andrei Bobrov 2011-6-28
[a b c]=unique(floor(A/100));
out = A(b)
  1 个评论
Michael
Michael 2011-6-28
nice thinking, this worked, but for some reason when i added the longer list i have, one of them didnt show up..

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