How to split a vector in to sub vectors?

조회 수: 310 (최근 30일)
Jayanta Deb
Jayanta Deb . 2017년 8월 16일
댓글: Pierre Mathieu . 2022년 10월 10일
I have a vector 'v' of size 8812x1,I want to split it into 20(or known length n) sub-vectors. eg. v = {1,2,3,...,8812}
I wish to see:
v3 = {42,43,44,...,62}
v20 = {...} % the last vector doesn't matter if it can have full 20 or not, it can / might get lesser number as its not fully possible to get a whole 20 elements divide equally with the size of the vector but obviously the vector v1 till v19 must have 20 elements.
Then I want to calculate the median from each sub divided vectors.
So it should be like m1 = median(v1), m2 = median(v2)... m20=median(v20)
I would appreciate if it is done with a loop
  댓글 수: 1
Stephen23 2017년 8월 16일
편집: Stephen23 님. 2022년 9월 8일
"I wish to see:"
v1 = {1,2,3,...,20}
v2 = {21,22,23,...,41}
v3 = {42,43,44,...,62}

댓글을 달려면 로그인하십시오.

채택된 답변

Stephen23 2017년 8월 16일
편집: Stephen23 님. 2017년 8월 16일
>> v = rand(8812,1);
>> b = 20; % block size
>> n = numel(v);
>> c = mat2cell(v,diff([0:b:n-1,n]));
>> z = cellfun(@median,c);
Or if you really want to use a loop, replace the last line with:
z = NaN(numel(c),1);
for k=1:numel(c)
z(k) = median(c{k});
  댓글 수: 2
Redouane Bouchou
Redouane Bouchou 2020년 6월 21일
thank you very much you are a genius

댓글을 달려면 로그인하십시오.

추가 답변 (2개)

José-Luis 2017년 8월 16일
v = rand(8812,1);
n = 20;
dummy = nan(20,ceil(numel(v)./n));
dummy(1:numel(v)) = v;
result = nanmedian(dummy)
  댓글 수: 2
Pierre Mathieu
Pierre Mathieu 2022년 10월 10일
Yes, very good!

댓글을 달려면 로그인하십시오.

ES 2017년 8월 16일
편집: ES 님. 2017년 8월 16일
v = [1:1:8812];
window_size = 20;
iCount = size(v,2);
iStartIDx = [1:window_size :iCount];
for iLoop=1:length(iStartIDx)-1
segment{iLoop} = v(iStartIDx(iLoop):iStartIDx(iLoop+1)-1);
med{iLoop} = median(segment{iLoop});
segment{iLoop+1} = v(iStartIDx(iLoop+1):end);
med{iLoop+1} = median(segment{iLoop+1});
  댓글 수: 3
José-Luis 2017년 8월 16일
편집: José-Luis 님. 2017년 8월 16일
This is rather wrong. On top of being incomplete, as pointed out by Jayanta:
There is no pre-allocation, a performance killer.
median is used both as a variable name and as a function. That's bound to be problematic.
Edit: latest comment was valid before answer being edited.

댓글을 달려면 로그인하십시오.


Help CenterFile Exchange에서 Creating and Concatenating Matrices에 대해 자세히 알아보기


Community Treasure Hunt

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

Start Hunting!

Translated by