find 1s in the Matrix

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Matin jaberi 2022-9-29

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回答： Matin jaberi 2022-9-30

Hi All,

I have a matrix 31996x66 and i need to write a if/else and for loop to do following.

the for loop must got through column 48 to 65 and anywhere the number is 1 it goes 36 cells back ()to the same row and save the number and if zero doesnt do anything.

for example:

if in row 500 coulumn 50 number is 1 then (50-36=14) it should go to row 500 column 14 and take the number and save in new table.

At the end the new Matrix should be 31996x(number of values for 1 in each row.)

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Matin jaberi 2022-9-29

It has got nothing to do with my clients requirements. its me wanting to automate the excel sheet so the matlab run and find the numbers for me rather than I go through excel sheet myself. And there is no othere structure.

Matin jaberi 2022-9-29

there might be many different ways to find the numbers I need but thats the simplest script i came up with to get what I need.

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Answer 1

Walter Roberson 2022-9-29

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https://ww2.mathworks.cn/matlabcentral/answers/1814215-find-1s-in-the-matrix#answer_1063640

在 MATLAB Online 中打开

firstcol = 48;
lastcol = 65;
offsetcol = 14;
idx = firstcol:lastcol;
offsetidx = idx-offsetcol;
result = YourMatrix(:,offsetidx) .* (YourMatrix(:,idx) == 1);

at the end the new Matrix should be 31996x(number of values for 1 in each row.)

You cannot do that; there could be a different number of 1's in each row and numeric matrices cannot have a different number of columns in each row.

The above code outputs an array the size of the subset, with 0 for the entries where the condition was not met.

I notice, by the way, that 62-14 = 48, so columns 48, 49, 50, 51 both act as numeric sources (values to be fetched) and as control information about which values are to be fetched. Is that overlap desired?

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Matin jaberi 2022-9-29

Thanks for your answer, the offset call is 36 not 14. As i mentioned before if column number is 50 then take 36 out and the desired col would be col 14.

Walter Roberson 2022-9-29

在 MATLAB Online 中打开

firstcol = 48;
lastcol = 65;
offsetcol = 36;
idx = firstcol:lastcol;
offsetidx = idx-offsetcol;
result = YourMatrix(:,offsetidx) .* (YourMatrix(:,idx) == 1);