Question

Convert the following pieces of code in just a single line of code. In all cases, A and B are arrays of size 5 x 5. Important: The expression "single line of code" implies a single command or equality. In other words, the code: X=A+1; X=X+B; is considered to be TWO lines.

(a) (4%) for i=1:5,

for j=1:5

A(i,j)=B(i,j)+1;

end

end

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(b) (4%) for i=1:3

for j=2:4

A(i,j)=B(i,j);

end

end

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(c) (5%) for i=1:3

for j=2:4

A(i,j)=B(i+2,j+1);

end

end

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(d) (4%) for i=1:5

for j=1:5

A(i,j)=1/(B(i,j))^2;

end

end

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(e) (5%) for i=1:5

for j=1:5

A(i,j)=B(6-i,j);

end

end

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Answer 1

Consider B

   17   24    1    8   15
   23    5    7   14   16
    4    6   13   20   22
   10   12   19   21    3
   11   18   25    2    9

for i=1:5
for j=1:5
A(i,j)=B(i,j)+1;
end
end

Above code can be replaced by single line using

A = B+1; %each element of A is populated from corresponding element of B by adding 1

>> A
A =

   18   25    2    9   16
   24    6    8   15   17
    5    7   14   21   23
   11   13   20   22    4
   12   19   26    3   10

>> B
B =

   17   24    1    8   15
   23    5    7   14   16
    4    6   13   20   22
   10   12   19   21    3
   11   18   25    2    9

>> B+1
ans =

   18   25    2    9   16
   24    6    8   15   17
    5    7   14   21   23
   11   13   20   22    4
   12   19   26    3   10

for i=1:3

for j=2:4

A(i,j)=B(i,j);

end

end

Can be replaced by

A(1:3,2:4) = B(1:3,2:4)

for i=1:3

for j=2:4

A(i,j)=B(i+2,j+1);

end

end

can be replaced by A(1:3,2:4)=B(3:5,3:5);

part d

for i=1:5

for j=1:5

A(i,j)=1/(B(i,j))^2;

end

end

Can be replaced by A = 1./(B.^2)

for i=1:5

for j=1:5

A(i,j)=B(6-i,j);

end

end

can be replaced by

A(1:5,1:5) = B(5:1,5:1);