error Unrecognized function or variable help me please :(!

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 !

[Stephen23]

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]

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]

Every signal represent two rows from the array( sign in red ) And what do you mean by overwrite ? How do I fix it ?

[Stephen23]

"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]

But in the question they tell me the input need to be "signalscell" .

[Stephen23]

"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]

yes .. but anyway i tried the way you wrote me and it still dosent work.

thr same error

[Stephen23]

"but anyway i tried the way you wrote me and it still dosent work. thr same error"

Sure. Did you read here and provide us with the requested information? Not yet.

[tal]

here:)

[Stephen23]

And also show us how you call the function.

[tal]

n=3;
load('signals.mat','signals')
PlotSignal(signals,n);

Answer 1

[Catalytic]

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

Answer 2

[Matt J]

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

Answer 3

[Stephen23]

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

signals = 6×56 cell array
  Columns 1 through 13

    {'time'}    {[      0]}    {[ 0.1164]}    {[ 0.2327]}    {[ 0.3491]}    {[ 0.4654]}    {[ 0.5818]}    {[ 0.6981]}    {[ 0.8145]}    {[ 0.9308]}    {[ 1.0472]}    {[ 1.1636]}    {[ 1.2799]}
    {'y1'  }    {[      7]}    {[ 7.5805]}    {[ 8.1531]}    {[ 8.7101]}    {[ 9.2440]}    {[ 9.7475]}    {[10.2139]}    {[10.6369]}    {[11.0106]}    {[11.3301]}    {[11.5911]}    {[11.7899]}
    {'time'}    {[-6.2832]}    {[-6.0505]}    {[-5.8178]}    {[-5.5851]}    {[-5.3523]}    {[-5.1196]}    {[-4.8869]}    {[-4.6542]}    {[-4.4215]}    {[-4.1888]}    {[-3.9561]}    {[-3.7234]}
    {'y2'  }    {[      4]}    {[ 4.1153]}    {[ 4.2244]}    {[ 4.3214]}    {[ 4.4011]}    {[ 4.4591]}    {[ 4.4924]}    {[ 4.4992]}    {[ 4.4790]}    {[ 4.4330]}    {[ 4.3637]}    {[ 4.2748]}
    {'time'}    {[-6.2832]}    {[-6.1668]}    {[-6.0505]}    {[-5.9341]}    {[-5.8178]}    {[-5.7014]}    {[-5.5851]}    {[-5.4687]}    {[-5.3523]}    {[-5.2360]}    {[-5.1196]}    {[-5.0033]}
    {'y3'  }    {[50.1000]}    {[49.7619]}    {[48.7522]}    {[47.0846]}    {[44.7816]}    {[41.8744]}    {[38.4022]}    {[34.4121]}    {[29.9579]}    {[25.1000]}    {[19.9040]}    {[14.4402]}

  Columns 14 through 25

    {[ 1.3963]}    {[ 1.5126]}    {[ 1.6290]}    {[ 1.7453]}    {[  1.8617]}    {[  1.9780]}    {[  2.0944]}    {[  2.2108]}    {[  2.3271]}    {[  2.4435]}    {[  2.5598]}    {[  2.6762]}
    {[11.9240]}    {[11.9915]}    {[11.9915]}    {[11.9240]}    {[ 11.7899]}    {[ 11.5911]}    {[ 11.3301]}    {[ 11.0106]}    {[ 10.6369]}    {[ 10.2139]}    {[  9.7475]}    {[  9.2440]}
    {[-3.4907]}    {[-3.2579]}    {[-3.0252]}    {[-2.7925]}    {[ -2.5598]}    {[ -2.3271]}    {[ -2.0944]}    {[ -1.8617]}    {[ -1.6290]}    {[ -1.3963]}    {[ -1.1636]}    {[ -0.9308]}
    {[ 4.1710]}    {[ 4.0580]}    {[ 3.9420]}    {[ 3.8290]}    {[  3.7252]}    {[  3.6363]}    {[  3.5670]}    {[  3.5210]}    {[  3.5008]}    {[  3.5076]}    {[  3.5409]}    {[  3.5989]}
    {[-4.8869]}    {[-4.7706]}    {[-4.6542]}    {[-4.5379]}    {[ -4.4215]}    {[ -4.3051]}    {[ -4.1888]}    {[ -4.0724]}    {[ -3.9561]}    {[ -3.8397]}    {[ -3.7234]}    {[ -3.6070]}
    {[ 8.7824]}    {[ 3.0072]}    {[-2.8072]}    {[-8.5824]}    {[-14.2402]}    {[-19.7040]}    {[-24.9000]}    {[-29.7579]}    {[-34.2121]}    {[-38.2022]}    {[-41.6744]}    {[-44.5816]}

  Columns 26 through 37

    {[  2.7925]}    {[  2.9089]}    {[  3.0252]}    {[  3.1416]}    {[  3.2579]}    {[  3.3743]}    {[  3.4907]}    {[  3.6070]}    {[  3.7234]}    {[  3.8397]}    {[  3.9561]}    {[  4.0724]}
    {[  8.7101]}    {[  8.1531]}    {[  7.5805]}    {[  7.0000]}    {[  6.4195]}    {[  5.8469]}    {[  5.2899]}    {[  4.7560]}    {[  4.2525]}    {[  3.7861]}    {[  3.3631]}    {[  2.9894]}
    {[ -0.6981]}    {[ -0.4654]}    {[ -0.2327]}    {[       0]}    {[  0.2327]}    {[  0.4654]}    {[  0.6981]}    {[  0.9308]}    {[  1.1636]}    {[  1.3963]}    {[  1.6290]}    {[  1.8617]}
    {[  3.6786]}    {[  3.7756]}    {[  3.8847]}    {[       4]}    {[  4.1153]}    {[  4.2244]}    {[  4.3214]}    {[  4.4011]}    {[  4.4591]}    {[  4.4924]}    {[  4.4992]}    {[  4.4790]}
    {[ -3.4907]}    {[ -3.3743]}    {[ -3.2579]}    {[ -3.1416]}    {[ -3.0252]}    {[ -2.9089]}    {[ -2.7925]}    {[ -2.6762]}    {[ -2.5598]}    {[ -2.4435]}    {[ -2.3271]}    {[ -2.2108]}
    {[-46.8846]}    {[-48.5522]}    {[-49.5619]}    {[-49.9000]}    {[-49.5619]}    {[-48.5522]}    {[-46.8846]}    {[-44.5816]}    {[-41.6744]}    {[-38.2022]}    {[-34.2121]}    {[-29.7579]}

  Columns 38 through 50

    {[  4.1888]}    {[  4.3051]}    {[  4.4215]}    {[ 4.5379]}    {[ 4.6542]}    {[ 4.7706]}    {[ 4.8869]}    {[ 5.0033]}    {[ 5.1196]}    {[ 5.2360]}    {[ 5.3523]}    {[ 5.4687]}    {[ 5.5851]}
    {[  2.6699]}    {[  2.4089]}    {[  2.2101]}    {[ 2.0760]}    {[ 2.0085]}    {[ 2.0085]}    {[ 2.0760]}    {[ 2.2101]}    {[ 2.4089]}    {[ 2.6699]}    {[ 2.9894]}    {[ 3.3631]}    {[ 3.7861]}
    {[  2.0944]}    {[  2.3271]}    {[  2.5598]}    {[ 2.7925]}    {[ 3.0252]}    {[ 3.2579]}    {[ 3.4907]}    {[ 3.7234]}    {[ 3.9561]}    {[ 4.1888]}    {[ 4.4215]}    {[ 4.6542]}    {[ 4.8869]}
    {[  4.4330]}    {[  4.3637]}    {[  4.2748]}    {[ 4.1710]}    {[ 4.0580]}    {[ 3.9420]}    {[ 3.8290]}    {[ 3.7252]}    {[ 3.6363]}    {[ 3.5670]}    {[ 3.5210]}    {[ 3.5008]}    {[ 3.5076]}
    {[ -2.0944]}    {[ -1.9780]}    {[ -1.8617]}    {[-1.7453]}    {[-1.6290]}    {[-1.5126]}    {[-1.3963]}    {[-1.2799]}    {[-1.1636]}    {[-1.0472]}    {[-0.9308]}    {[-0.8145]}    {[-0.6981]}
    {[-24.9000]}    {[-19.7040]}    {[-14.2402]}    {[-8.5824]}    {[-2.8072]}    {[ 3.0072]}    {[ 8.7824]}    {[14.4402]}    {[19.9040]}    {[25.1000]}    {[29.9579]}    {[34.4121]}    {[38.4022]}

  Columns 51 through 56

    {[ 5.7014]}    {[ 5.8178]}    {[ 5.9341]}    {[ 6.0505]}    {[ 6.1668]}    {[ 6.2832]}
    {[ 4.2525]}    {[ 4.7560]}    {[ 5.2899]}    {[ 5.8469]}    {[ 6.4195]}    {[ 7.0000]}
    {[ 5.1196]}    {[ 5.3523]}    {[ 5.5851]}    {[ 5.8178]}    {[ 6.0505]}    {[ 6.2832]}
    {[ 3.5409]}    {[ 3.5989]}    {[ 3.6786]}    {[ 3.7756]}    {[ 3.8847]}    {[      4]}
    {[-0.5818]}    {[-0.4654]}    {[-0.3491]}    {[-0.2327]}    {[-0.1164]}    {[      0]}
    {[41.8744]}    {[44.7816]}    {[47.0846]}    {[48.7522]}    {[49.7619]}    {[50.1000]}

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

[tal]

thank you so much for your help ! i really appriciate it . do the way i wrote the function it isnt corect at all ?

[Stephen23]

"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]

i dont get it it dosent work with the script i sent here / and in the part of the practice i must use this script so how come it dosent work ?

and the huge problem i had is that i havents used the input i eneter in the function as the proffesor said ..

whats wrong with the code again ? i get an error in the second line ..

and can you please show me how you solve it with the script i sent here ?

function PlotSignal(signalsCell, n)
X=signalsCell(2*n-1,2*n);
Y = cell2mat(signalsCell(2:end));
figure;
plot(X,Y,'k');
end

[Walter Roberson]

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]

n=3;
load('signals.mat','signals')
PlotSignal(signals,n);

Why this command isn't ok?

[Walter Roberson]

What is the error message?

[Time]

The same error I wrote in the begging itdosen recognize signalscelll

[Walter Roberson]

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]

Well I'll do it tomorrow morning I am not near the computer anymore . What does who's command does ? And did you try to run the function maybe on your own and know what is the problem ? Fyi I added here a fille of array .

[Voss]

@Time: I get a different error (using the mat file provided by @tal):

n=3;
load('signals.mat','signals')
PlotSignal(signals,n);

Error using cell2mat
All contents of the input cell array must be of the same data type.

Error in solution>PlotSignal (line 7)
Y = cell2mat(signalsCell(2:end));

function PlotSignal(signalsCell, n)
X=signalsCell(2*n-1,2*n);
Y = cell2mat(signalsCell(2:end));
figure;
plot(X,Y,'k');
end

[Voss]

@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