For Loop Moving Through Array

Question

HoboHarry 2018-8-30

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编辑： Stephen23 2018-8-30

Trying to write a for loop that moves through an array with 2 columns and 15 rows. The code i've written just provides the same results 15 times for the 1st cells of the array. i'm guessing i need to nest it somehow but i have no idea, a few clues on where i'm wrong would be great

X = Var1;  
Y = Var2;  
Z = 29;
TableCreate = table(X,Y);
Array = table2array(TableCreate);
for N = 1:length(Array)
    A = (Array(1,1)*Z)/Array(1,2);
    disp (A)
end

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Stephen23 2018-8-30

编辑：Stephen23 2018-8-30

"i'm guessing i need to nest it somehow but i have no idea, a few clues on where i'm wrong would be great"

Inside the loop you need to use indexing into A:

https://www.mathworks.com/help/matlab/getting-started-with-matlab.html

Even better, don't use any loop at all:

https://www.mathworks.com/help/matlab/matlab_prog/vectorization.html

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Answer 1

Sven 2018-8-30

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The problem is that you are not using the index N.

A = (Array(1,1)*Z)/Array(1,2);

This line doesn't change, so you will get the same output 15 times. A nested loop would look like this:

 [row,col] = size(B);
 for N = 1:col
     for M = 1:row
         A = (B(M,N)*Z)/B(1,2);
         disp (A)
     end
 end

The first loop will start at column 1, then the second loop goes through all rows. After that it repeats with column 2 and so on if you have more columns. Depending on how you want to manipulate the entries you have to use both indexes accordingly.

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Answer 2

Dennis 2018-8-30

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编辑：Dennis 2018-8-30

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You overwrite A in every iteration and you are calculating the same value over and over again (not using N anywhere).

I am not sure why you create a table and turn it into an array afterwards.

MWE:

x=randi(3,3);
y=rand(3);
array=[x, y];
A=zeros(size(array,2),1);
for N=1:size(array,2)
A(N)=array(1,N)+array(2,N);  %use N to access array index, i have no clue what you try to calculate so my example is random
end
disp(A)