How to select number in csv file if different than 0 and refer to another column to calculate the difference?

Hello,

I know the question isn't clear but: I have a csv file containing data from graphs from a video. Those are values from each frame from the video. Using excel, I chose the values higher than a certain number, thus I have holes in my matrix (which is what I want).

The first column corresponds to a distance, which is my x. The second column corresponds to grey values, which is my y from the first frame of my video. The third column corresponds to grey values, which is my y from my second frame from my video, and so on.

What I would like to have at the end it's a graph size of my object in y versus the time (so my frames). So I am trying to have a code like:

If Y is different from 0 in frame 1, then Xmax-Xmin in the first column

But I need to learn how to write this code.

If anyone has an idea, it would be great! Thanks for your help!

Answer 1

[Jayant Gangwar]

Hi,

First you need to import the data to MATLAB, you can use 'readmatrix', refer to this documentation for more information about this function.

After you have the data in a matrix you can use 'if' statement to check if your condition is satisfied and then use 'max' & 'min' functions to do the calculation you require. Refer to below documentation for more information about these functions-

Maximum elements of an array - MATLAB max (mathworks.com)

Minimum elements of an array - MATLAB min (mathworks.com)

For example the code would look similar to the following

>> mat = readmatrix('my_data.csv');
>> if(Y!=0)
>>      var = max(mat(:,1)) - min(mat(:,1));    
>> end