How can I make a column appending columns which are of size of sum of other column?

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Totanly
Totanly 2019-1-8
回答： Andrei Bobrov 2019-1-9
suppose i have three matrix of same length lat, lon and CG as
lat=[1 2 3 4 5];CG=[5 10 20 11 12];
i want to make like
lat=[lat(1).*ones(CG(1),1);lat(2).*ones(CG(2),1);lat(3).*ones(CG(3),1);lat(4).*ones(CG(4),1);lat(5).*ones(CG(5),1);];
how to do it with loop for large vectors?
i tried like this
n=length(CG)-1;
for i=1:n
kk=lat(i).*ones(CG(i),1);
kk1=[kk;lat(i+1).*ones(CG(i+1),1)]
end
it doesnot work.

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采纳的回答

Stephen23
Stephen23 2019-1-9
编辑：Stephen23 2019-1-9
>> lat = [1,2,3,4,5];
>> CG = [5,10,20,11,12];
>> V = cell2mat(arrayfun(@(v,n)v*ones(n,1),lat(:),CG(:),'uni',0))
V =
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
5
5
Or, if you really want to use a loop:
N = numel(lat);
C = cell(N,1);
for k = 1:N
C{K} = lat(k).*ones(CG(k),1);
end
V = vertcat(C{:})

更多回答（3 个）

TADA
TADA 2019-1-8
lat=[1 2 3 4 5];
CG=[5 10 20 11 12];
output = repelem(lat', CG, 1);
Totanly
Totanly 2019-1-9
lat2=lat(1).*ones(CG(1),1);
for k=2:length(CG)
lat2=[lat2;lat(k).*ones(CG(k),1)];
end
i made like this but its taking long time for large data.
  2 个评论
TADA
TADA 2019-1-9
try this:
lat=[1 2 3 4 5];
CG=[5 10 20 11 12];
windowIndices = [0 cumsum(CG)];
lat2=zeros(1,sum(CG));
for k=1:length(CG)
lat2(windowIndices(k)+1:windowIndices(k+1)) = repmat(lat(k), 1, CG(k));
end

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Andrei Bobrov
Andrei Bobrov 2019-1-9
J = cumsum(CG);
ii = zeros(J(end),1);
ii(J-CG+1) = 1;
out = lat(cumsum(ii));

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