my question is after ploting (x,y) , i want to count the number of signals that is above 0.5 at time for example : 1.05e-7, how to do that in matlab

i want to count the values from data set (:,2:5) that is above 0.5 at specific time

data_1 = load('ay.csv')
x = data_1(:,1)
y = data_1(:,2:5)
plot(x,y)
count=0
n= 17059 
m=4

for r=1:n
    for c=1:m  
        if y(r,c)> 0.5 & (x == 1.05e-7) 
               count= count+1
        end
    end   
end
count
    

[Jan]

What is your question?

Does load('ay.csv') work? load works with MAT files and a specific set of text files only.

x is a vector. Then x==1.05e-7 is a vector also. The if condition must be a scalar. Therefore Matlab inserts an all() implicitly. But is this wanted?

Remember that comparisons of floating point numbers are fragile. 1.05e-7 and 1.0499999999e-7 might be displayed as the same value in the command wirndow, but they differ. Using a range is safer.

[Hagar Hendy]

yes loading works, my question is after ploting (x,y) , i want to count the number of signals that is above 0.5 at time for example : 1.05e-7.

Answer 1

[Torsten]

xx = 1.05e-7;
[~,i] = min(abs(x-xx));
count = nnz(y(i(1),:) > 0.5)

[Hagar Hendy]

thanks a lot , it works