selecting certain values from a list

18 views (last 30 days)
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

Accepted Answer

Paulo Silva
Paulo Silva on 28 Jun 2011
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
  6 Comments
Sean de Wolski
Sean de Wolski on 28 Jun 2011
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 on 28 Jun 2011
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.

Sign in to comment.

More Answers (1)

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

Sign in to comment.

Categories

Find more on Programming in Help Center and File Exchange

Tags

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!