Can you create a matrix using a for loop

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Maryal 2017-12-9

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https://ww2.mathworks.cn/matlabcentral/answers/372036-can-you-create-a-matrix-using-a-for-loop

评论： Lam Nguyen Van 2020-3-11

Is possible to create a matrix by just using for loops Thanks

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chandrapal Singh 2017-12-9

what type of matrix? can you please provide more details regarding this query?

Stephen23 2017-12-9

"Is possible to create a matrix by just using for loops"

Yes.

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Answer 1

Amy 2017-12-11

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https://ww2.mathworks.cn/matlabcentral/answers/372036-can-you-create-a-matrix-using-a-for-loop#answer_295685

Look at the first example in the documentation for 'for': https://www.mathworks.com/help/matlab/ref/for.html

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Answer 2

Lam Nguyen Van 2020-3-10

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Hi,

I want to creat matrices automatically with for loop in Matlab?

phi1=30; phi2=45; phi3=90;

After running the code I want to have a matric A with the following elements:

A=[sin(phi1) cos(phi1) sin(phi1)*cos(phi1);

sin(phi2) cos(phi2) sin(phi2)*cos(phi2);

sin(phi3) cos(phi3) sin(phi3)*cos(phi3);]

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chandrapal Singh 2020-3-10

lengthy code for query

phi1=30; phi2=45; phi3=90;

rows= 3;

cols=3;

A= zeros(3);

row_num=1;

col_num =1;

for i = 1: 3

if row_num ==1

A(1,i)= sin(phi1);

col_num =col_num+1;

if col_num ==2

A(1,col_num)= cos(phi1);

col_num =col_num+1;

end

if col_num ==3

A(1,col_num)= sin(phi1)*cos(phi1);

col_num =col_num+1;

end

row_num=row_num+1;

end

col_num=1;

if row_num ==2

A(2,i)= sin(phi2);

col_num =col_num+1;

if col_num ==2

A(2,col_num)= cos(phi2);

col_num =col_num+1;

end

if col_num ==3

A(2,col_num)= sin(phi2)*cos(phi2);

col_num =col_num+1;

end

row_num=row_num+1;

end

col_num=1;

if row_num ==3

A(3,i)= sin(phi3);

col_num =col_num+1;

if col_num ==2

A(3,col_num)= cos(phi3);

col_num =col_num+1;

end

if col_num ==3

A(3,col_num)= sin(phi3)*cos(phi3);

col_num =col_num+1;

end

row_num=row_num+1;

end

Lam Nguyen Van 2020-3-10

Thanks!

I want to use

for i=1:3

for j=1:3

A(i,j)=...;

end

I want shorter code.

Lam Nguyen Van 2020-3-11

I did it. I used for loop and function.

phi=[30, 45, 90];

n=length(phi);

[e]=xuat_vecto(phi1);

A=zeros(n,3);

for i=1:n

[d]= xuat_vecto (phi(i));

A(i,:)=[d];

end

A

function [e]=xuat_vecto(alpha)

[a, b, c]=ham_luong_giac (alpha);

e=[a, b, c];

end

function [a1, a2, a3] = ham_luong_giac (phi)

a1=sin(phi);

a2=cos(phi);

a3=sin(phi)*cos(phi);

xuat= [a1, a2, a3];

end

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Can you create a matrix using a for loop

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