how to read complex file data to matrix

4 vues (au cours des 30 derniers jours)
vincent lin
vincent lin le 17 Jan 2020
Modifié(e) : per isakson le 18 Jan 2020
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
  2 commentaires
stozaki
stozaki le 17 Jan 2020
Could you attach a real text file?
vincent lin
vincent lin le 17 Jan 2020
yes. a.txt added

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per isakson
per isakson le 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 commentaire
vincent lin
vincent lin le 17 Jan 2020
Modifié(e) : per isakson le 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))];

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Walter Roberson
Walter Roberson le 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.

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