how to read complex file data to matrix

12 views (last 30 days)
I have a.txt file, with complex data. the format is
1.958138021e-02 0.64646110658609712285 + 0.093290941560866688653j
1.958139648e-02 0.32117256288141476928 - 0.061542254916540022058j
1.958141276e-02 -0.22359569118086644601 + 0.3585713533321416846j
1.958142904e-02 -0.22397218216792619261 + 0.082213621398327246803j
1.999960938e-02 0
1.999962565e-02 0
1.999964193e-02 0
1.999965820e-02 0
2.000000000e-02 0.10412797744247889731 + 0.0081123700776114041067j
There's space between + and -. how can I read this file into a matrix with seperated I part and Q part.
like
1.958138021e-02 0.64646110658609712285 0.093290941560866688653
...
1.999960938e-02 0 0
2.000000000e-02 0.10412797744247889731 0.0081123700776114041067

Accepted Answer

per isakson
per isakson on 17 Jan 2020
Following Walter's advise
%%
chr = fileread('a.txt');
%%
chr = strrep( chr, ' + ', '+' );
chr = strrep( chr, ' - ', '-' );
cac = textscan( chr, '%f%f' );
%%
M = cat( 2, cac{1}, real(cac{2}), imag(cac{2}) );
>> M(1:3,:)
ans =
0 0.10413 0.0081124
1.6276e-08 -0.04608 -0.073765
3.2552e-08 -0.038321 0.076231
  1 Comment
vincent lin
vincent lin on 17 Jan 2020
Edited: per isakson on 18 Jan 2020
thank you. This works and is fast. I find there's another code by reading line by line. It works but is very slow. Your method is faster
fid = fopen ('a.txt','r');
ii = 1;
while ~feof(fid)
acorrente(ii, :) = str2num(fgets(fid));
ii = ii + 1;
end
fclose(fid);
data = [real(acorrente(:,1)) real(acorrente(:,2)) imag(acorrente(:,2))];

Sign in to comment.

More Answers (1)

Walter Roberson
Walter Roberson on 17 Jan 2020
Sometimes easiest is to read the file as a character vector, use regexp to remove the space around the sign of the imaginary part, and then textscan. textscan and other numeric formats can read complex values when there is no space.
Or read the file as string and regexp to change lines that do not end in j to append + 0j on them. With all lines having the same format you can easily textscan to extract real and imaginary separately.

Tags

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!