How to include complex numbers in fprintf function?

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Robbie McCormack
Robbie McCormack 2017-11-28
评论： Walter Roberson 2025-1-24
lambda = [1.064e-6];
R = [30];
w=[0.001];
q = (1./R- i* lambda./pi./w.^2).^(-1);
a=1;
p=1;
m=1;
probe_r=linspace(0,0.003,100);
probe_theta=linspace(0,0.003,100);
rseed=[0*max(w):max(w)/30:3*max(w)];
thetaseed=[0:360]*pi/180;
[r,theta]=meshgrid(rseed,thetaseed);
E=LaguerreGaussianE([p,m,q,lambda,a],r,theta);
V=interp2(r,theta,E,probe_r,probe_theta);
column_names = {'r', 'theta', 'V'};
fid = fopen('fidtext.txt','wt');
fprintf(fid, '%s ', column_names{:});
fprintf(fid, '\n');
block_of_data = [probe_r, probe_theta, V];
fmt = repmat('%15g ', 1, 3);
fmt(end:end+1) = '\n';
fprintf(fid, fmt, block_of_data.');
fclose(fid);
With the current code I have I get a .txt file of only the real numbers from my function V along with the values of probe_r and probe_theta. How do I alter this to produce both the real and complex numbers as a 3 column .txt file of r, theta and V as I am unable to see a formatSpec to include complex numbers.

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采纳的回答

Star Strider
Star Strider 2017-11-28
编辑：Star Strider 2017-11-28
you have to write the real and complex parts separately.
Example —
x = sqrt(-2);
fprintf(fid, '%f%+fj\n', real(x), imag(x))
0.000000+1.414214j
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Walter Roberson
Walter Roberson 2025-1-24
Ran in:
@NAVNEET
V = [-1 - 1i
-1 + 0i
-1 + 1i
0 - 1i
0 - 0i
0 + 1i
1 - 1i
1 + 0i
1 + 1i];
fid = 1;
fprintf(fid, '%f%+fi\n', [real(V(:)), imag(V(:))].');
-1.000000-1.000000i -1.000000+0.000000i -1.000000+1.000000i 0.000000-1.000000i 0.000000+0.000000i 0.000000+1.000000i 1.000000-1.000000i 1.000000+0.000000i 1.000000+1.000000i
You can see that negative imaginary parts are automatically handled.
The key here is the %+ specification, which instructs that the appropriate sign of the value is to be inserted.

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更多回答（1 个）

Ken Crandall
Ken Crandall 2020-2-6
This works fine for a single complex number. If you replace x with an array, the reals come first followed by all the imaginaries.
For example:
rxSignal=[1.1+1j*2.2 3.3+1j*4.4 5.5+1j*6.6]
fileID=fopen('rxSignal.txt','w')
fprintf(fileID,'%f%+fj\n',real(rxSignal(:)),imag(rxSignal(:)));
fclose(fileID)
When you read the text file, you get:
1.100000+3.300000j
5.500000+2.200000j
4.400000+6.600000j
Here you see the reals filling the first three slots and the imaginaries filling the last three slots.
How to fix this without writing a for loop to do one at a time?
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Star Strider
Star Strider 2020-2-7
No apology necessary!
It’s just that it’s important to read the code carefully and understand how it works.

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