array manipulation using location

Hello, I have an array X and another array Y which has some of the indices in array X. I need a new array which will have the X value in the corresponding Y element(index location in X) and zero otherwise. can anybody help me? this is what I tried but it's not working. I'm only getting one value.
X=[11 22 51 28 93 11 124 153 165 176 17 18 19 20];
iY=[1 3 5 9];
for m=1:length(X)
for n=1:length(iY)
if m~=iY(n)
combined_matrix(m)=0;
elseif m==iY(n)
combined_matrix(m)=X(iY(n));
end
end
end

 Respuesta aceptada

Birdman
Birdman el 25 de Dic. de 2017
Editada: Birdman el 25 de Dic. de 2017
Do you mean this?
X(~ismember(1:numel(X),iY))=0

3 comentarios

SSG_newbiecoder
SSG_newbiecoder el 26 de Dic. de 2017
Editada: SSG_newbiecoder el 26 de Dic. de 2017
if I assign combined_matrix as a zero array with size same as that of X before the for loop, I'll get it. Sorry for asking such a silly doubt
X=[11 22 51 28 93 11 124 153 165 176 17 18 19 20];
iY=[1 3 5 9];
combined_matrix=zeros(size(X));
for m=1:length(X)
for n=1:length(iY)
if m==iY(n)
combined_matrix(m)=X(iY(n));
end
end
end
Birdman
Birdman el 26 de Dic. de 2017
Editada: Birdman el 26 de Dic. de 2017
Yes but you should avoid using for loops while you can. My solution is really simple. Of course preallocation is something you should do for that case but for loop is not necessary here.
SSG_newbiecoder
SSG_newbiecoder el 26 de Dic. de 2017
Editada: SSG_newbiecoder el 26 de Dic. de 2017
@Birdman OK,thank you..

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el 25 de Dic. de 2017

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