Size doesn't match Value?

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Theodore 2023-1-20

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移动：DGM 2023-1-22

I'm reading in a .mat variable, a column of numbers, which is appearing in my workspace as a "20,229 x 1 double"

I'd like to now create a for loop which loops x times (where x = 20,229), but when I go to find the size of the variable,

it shows as 25, not 20,229?

How do I properly extract this value for use? It is a column vector. Numel() or size() don't seem to work

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Guilherme 2023-1-20

Hi, Theodore!

Can you please share a extract of your code so that someone could try to figure out why it's not working?

Ideally you're trying to do something like this, right?

x = zeros(20000,1);

for i = 1:20000

% do your stuf

your_value = i;

x(i) = your_value;

end

numel(x) %% length(x) should prompt the same result. Size will have two informations: number of lines and number of columns.

Theodore 2023-1-20

sizeOfDoubleQ.PNG

Yes, apologies for blurring the variables (company confidentiality). 'Blue' and 'Purple' are equal length columns, each being read from a .mat file to have a size of '25'

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Answer 1

DGM 2023-1-20

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移动：DGM 2023-1-22

在 MATLAB Online 中打开

You're finding the size of the char vector, not the variable.

myvariable = rand(100,1);
size(myvariable) % this is a 100x1 numeric vector
ans = 1×2
   100     1
size('myvariable') % this is a 1x10 char vector
ans = 1×2
     1    10