separating columns in data files

Hello!

I have a data file, attached. I would like to only obtain the positive values of this file, i.e. only the first column and then make a subsequent text file.

This file is the output of fft on a data file, thus it contains both real values and imaginary values.

Thank you!

Karla

Answer 1

[Walter Roberson]

You only have one column of data -- those are complex numbers.

"Only positive" would restrict to just the very first point. Every other point is complex-valued with non-zero imaginary part, and so could not be said to be positive.

[Walter Roberson]

Y = readmatrix('Y.txt');
Ypositive = Y(real(Y)>0);

writematrix(Ypositive, 'Ypositive.txt');

dbtype Ypositive.txt 1:10

1     3464.328258+0i
2     0.000674780887635507-0.0611685605125578i
3     0.00285671163585732-0.0454525189854182i
4     0.00421265752004274-0.0361586728286951i
5     0.00516887965437718-0.0294093650495321i
6     0.00573141263822663-0.025892194218674i
7     0.00562182728276639-0.022676055193402i
8     0.00575974729039785-0.0200011190135066i
9     0.00579318668150108-0.0180308127612939i
10    0.0056623294612308-0.0162200839423056i