error Unrecognized function or variable help me please :(!
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the question(the part i tried to solve):
Write a function called PlotSignal, the function will display on a graph the signal it receives.
1.1. The function inputs are:
1.1.1 signalsCell – an object of cell array type, (each pair of rows in it represents one letter, see details
At the end of the question(
1.1.2 n – the number of the signal to be displayed
1.2. The function does not return any value.
1.3. The letter n from the array of cells should be displayed on a graph according to the following detail:
1.3.1. The signal color shall be black.
as you see i have an error in my code i dont know how to load the input in the workspace i tried to do
function PlotSignal(signalsCell, n)
signalsCell=signals(2*n-1:2*n,:);
Y=cell2mat(signalsCell);
X=signals(n,:);
figure;
plot(X,Y,'k');
end
the eroor
Unrecognized function or variable 'signalsCell'.
can someone please help me ? even to write all over again the function please?
thanks !
11 Comments
Stephen23
on 9 Feb 2024
How are you calling the function?
My guess is that you are calling it something like this:
PlotSignal(signalsCell, n)
In which case... what value/s do you expect signalsCell to have?
Please show us exactly how you define its input arrays, and exactly how you call this function.
Torsten
on 9 Feb 2024
function PlotSignal(signalsCell, n)
signalsCell=signals(2*n-1:2*n,:);
"signalsCell" is the input to your function "PlotSignal" and you overwrite it by "signals(2*n-1:2*n,:)". This must be wrong.
Time
on 10 Feb 2024
Stephen23
on 10 Feb 2024
"And what do you mean by overwrite ? How do I fix it ?"
What you are doing, overwriting the input argument SIAGNALSCELL and not definiing SIGNALS anywhere:
function PlotSignal(signalsCell, n)
signalsCell=signals(2*n-1:2*n,:);
What you probably intended to do:
function PlotSignal(signals,n)
signalsCell = signals(2*n-1:2*n,:);
Time
on 10 Feb 2024
Stephen23
on 10 Feb 2024
"But in the question they tell me the input need to be "signalscell" ."
Sure, is there something stopping you from changing the variable names youself?
Time
on 10 Feb 2024
tal
on 10 Feb 2024
here:)
Stephen23
on 10 Feb 2024
And also show us how you call the function.
tal
on 10 Feb 2024
n=3;
load('signals.mat','signals')
PlotSignal(signals,n);
Answers (3)
signalsCell=load('signals').signals;
PlotSignal(signalsCell, 3)
function PlotSignal(signalsCell, n)
Headings=signalsCell(:,1);
Table=cell2table(signalsCell(:,2:end)');
plot(Table, 2*n-1,2*n,Color='k');
xlabel(Headings{2*n-1});
ylabel(Headings{2*n});
end
Perhaps as follows?
signalsCell=load('signals').signals;
PlotSignal(signalsCell, 3)
function PlotSignal(signalsCell, n)
signalsCell=num2cell(cell2mat(signalsCell(:,2:end)),2);
X=signalsCell(1:2:end);
Y=signalsCell(2:2:end);
figure;
plot(X{n},Y{n},'o-k');
end
That really is very bad data design: one single numeric array would be much better than storing lots of numeric scalars in a huge cell array. Your tutor tried to replicate something like a TABLE... but should just use a TABLE. You will have to unlearn half of what they show you :(
signals = load('signals.mat').signals
PlotSignal(signals,1)
PlotSignal(signals,3)
function PlotSignal(inp,n)
sig = "y"+n;
idx = find(strcmpi(sig,inp(:,1)));
X = cell2mat(inp(idx-1,2:end));
Y = cell2mat(inp(idx-0,2:end));
plot(X,Y,'+-k');
legend(sig)
end
11 Comments
tal
on 10 Feb 2024
thank you so much for your help ! i really appriciate it . do the way i wrote the function it isnt corect at all ?
"do the way i wrote the function it isnt corect at all ?"
It works when you fix the bugs and call it correctly. For example:
signals = load('signals.mat').signals;
PlotSignal(signals,3)
function PlotSignal(signalsCell, n)
X = cell2mat(signalsCell(2*n-1,2:end));
Y = cell2mat(signalsCell(2*n-0,2:end));
plot(X,Y,'k');
end
Time
on 13 Feb 2024
Walter Roberson
on 13 Feb 2024
You would get an error in the second line if you pressed the green Run button to execute the code. When you press the green Run button to execute the code, it executes the function with no input parameters.
You need to go down to the command line and
signals = load('signals.mat').signals;
PlotSignal(signals,3)
Time
on 13 Feb 2024
Edited: Walter Roberson
on 13 Feb 2024
Walter Roberson
on 13 Feb 2024
What is the error message?
Time
on 13 Feb 2024
Walter Roberson
on 13 Feb 2024
As a test, add a whos command near the top,
function PlotSignal(signalsCell, n)
whos
X=signalsCell(2*n-1,2*n);
Y = cell2mat(signalsCell(2:end));
figure;
plot(X,Y,'k');
end
and see what the result is
Time
on 13 Feb 2024
@Time: However, if I modify the function as suggested by Stephen, it runs fine:
n=3;
load('signals.mat','signals')
PlotSignal(signals,n);
function PlotSignal(signalsCell, n)
X = cell2mat(signalsCell(2*n-1,2:end));
Y = cell2mat(signalsCell(2*n-0,2:end));
plot(X,Y,'k');
end
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