MATLAB: How to output and name variables generated in ‘for’ loop into workspace.

MATLABnaming for-loop variable sine tone audio num2str workspace output

Wrote a little function to generate random frequency sine tones. I would like each tone generated to be output into the workspace as a variable with name determined by output and input arguments and randomly generated variables (namely, tone freqency). I figured how to put the generated tones into a cell, but that's not what I want; I just want the simple, discrete audio vectors (1 x Nsamples), etc.

Comment lines in the code below explain what I'm trying to achieve a bit further. I KNOW this is a very simple thing, but the solution escapes me, and I'm not sure where to look in the documentation.

Thanks in advance!

function [Signal] = SineWave(Flower, Fupper, Amp, Fs, Time, NumTones)
% Random frequency sine tone generator ...
% Generates a specified number of sine tones at specified length and
% amplitude with random frequency values within specified upper and lower limits.
for i = 1 : NumTones
Frequency   =   randi([Flower Fupper]);
t           =   0:1/Fs:Time;
Signal      =   Amp * sin(2*pi*Frequency*t);
sound(Signal, Fs)
pause(Time)
% ADD LINES TO OUTPUT EACH TONE GENERATED AS 'Signal(Frequency)_i'
% Output variables named according to the [Signal] output argument followed by the randomly generated
% frequency value and number (i). For example, for five random sine tones (NumTones), five variables should be outputted named thusly: 
% 'Signal250_1' 'Signal440_2' 'Signal1000_3' 'Signal330_4' 'Signal2500_5'
end

Best Answer

Can you define variables with numbered names like Tone200_1, Tone400_2, etc, ... ? Yes.

Should you do this? Generally we recommend against it.

Related Solutions

MATLAB: Getting shifted frequency curves instead of normal ones

The time vectors were stored in categorical datatype (bad choice). Therefore, you were getting that unexpected plots. Try the following code. I have only added lines before the plot() statement.

nexttile
Fd1 = double(split(string(fdim1(1:end-1)) , ","));
Fd1 = Fd1(:,1);
timefdim1 = duration(string(timefdim1));
plot(timefdim1(1:end-1),Fd1);
xticks([timefdim1(1) timefdim1(end-1)]);
yticks([Fd1(1) Fd1(end-1)]);
title('dimfrequency 1')
xlabel('Uhrzeit in [HH:MM:SS]')
ylabel('Frequenzintervall 150kHz - 80 MHz')
nexttile
Fd2 = double(split(string(fdim2(2:end-1)) , ","));
Fd2 = Fd2(:,1);
timefdim2 = duration(string(timefdim2));
plot(timefdim2(2:end-1),Fd2);
xticks([timefdim2(2) timefdim2(end-1)]);
yticks([Fd2(2) Fd2(end-1)]);
title('dimfrequency 2')
xlabel('Uhrzeit in [HH:MM:SS]')
ylabel('Frequenzintervall 80 MHz - 1 GHz')
nexttile
Fd3 = double(split(string(fdim3(3:end-1)) , ","));
Fd3 = Fd3(:,1);
timefdim3 = duration(string(timefdim3));
plot(timefdim3(3:end-1),Fd3);
xticks([timefdim3(1) timefdim3(end-1)]);
yticks([Fd3(1) Fd3(end-1)])
title('dimfrequency 3')
xlabel('Uhrzeit in [HH:MM:SS]')
ylabel('Frequenzintervall 1 GHz - 2,7 GHz')
nexttile
F1 = double(split(string(fbll1(1:end-1)) , ","));
F1 = F1(:,1);
timefbll1 = duration(string(timefbll1));
plot(timefbll1(1:end-1),F1);
xticks([timefbll1(1) timefbll1(end-1)]);
yticks([F1(1) F1(end-1)]);
title('bllfrequency 1')
xlabel('Uhrzeit in [HH:MM:SS]')
ylabel('Frequenzintervall 150kHz - 80 MHz')
nexttile
F2 = double(split(string(fbll2(2:end-1)) , ","));
F2 = F2(:,1);
timefbll2 = duration(string(timefbll2));
plot(timefbll2(2:end-1),F2);
xticks([timefbll2(2) timefbll2(end-1)]);
yticks([F2(2) F2(end-1)]);
title('bllfrequency 2')
xlabel('Uhrzeit in [HH:MM:SS]')
ylabel('Frequenzintervall 80 MHz - 1 GHz')
nexttile
F3 = double(split(string(fbll3(3:end-1)) , ","));
F3 = F3(:,1);
timefbll3 = duration(string(timefbll3));
plot(timefbll3(3:end-1),F3);
xticks([timefbll3(1) timefbll3(end-1)]);
yticks([F3(1) F3(end-1)])
title('bllfrequency 3')
xlabel('Uhrzeit in [HH:MM:SS]')
ylabel('Frequenzintervall 1 GHz - 2,7 GHz')

MATLAB: Plotting frequency curves in one figure

The error we see is happening in the split function because not every string in string(FEC_fb2(1:end-1)) has the same number of commas, referred to as "matches" in the error message.

Hopefully this example demonstrates the issue a little more clearly.

>> split(["a,b";"c,d"],",")
ans = 
  2×2 string array
    "a"    "b"
    "c"    "d"
    
>> split(["a";"c,d"],",")
Error using split
Element 2 of the text contains 1 matches while the previous elements have 0. All
elements must contain the same number of matches.

You can get around this issue by calling split separately on each string and assigning the results to a cell array, which allows elements of different lengths.

strs = ["a";"c,d"];
strsSplit = cell(1,numel(strs));
for i = 1:numel(strs)
    strsSplit{i} = split(strs(i),",");
end
strsSplit

which outputs

strsSplit =
  1×2 cell array
    {["a"]}    {2×1 string}
>> strsSplit{2}
ans = 
  2×1 string array
    "c"
    "d"

Alternatively, you can use arrayfun.

>> arrayfun(@(s)split(s,","), ["a";"c,d"], "UniformOutput", false)
ans =
  2×1 cell array
    {["a"     ]}
    {2×1 string}

Best Answer

Related Solutions

MATLAB: Getting shifted frequency curves instead of normal ones

MATLAB: Plotting frequency curves in one figure

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