plot with input arguments

i want to subplot 4 string containg cell array from ( sin, cos, tan,sinh) and vector (+,o,*,x,s) and the mathmatical function should be ploted in interval (-2pi,2pi)with step 0.3

Answer 1

[Walter Roberson]

funs_cell = {'sin', 'cos', 'tan', 'sinh'};
markers = {'+', 'o', '*', 'x', 's'};
funs = cellfun(@str2fun, funs_cell, 'uniform', 0);
for K = 1 : length(funs)
    plot(x, funs{K}(x), markers{K}, 'DisplayName', funs_cell{K});
    hold on
end

[Roger Nadal]

If I pass more value in fun_cell then it should select only four value while passing function so how it should work?

[Walter Roberson]

for K = 1 : 4

Or did you want it to select 4 at random?

[Roger Nadal]

yes i want to select random four and it should plot 4 subplot in one figure like function

abc({sin', 'sinh', 'cos', 'cosh'}, ['o', 'x', 's', '*']) it should plot four in one figure.

[Walter Roberson]

It would be better if the markers were passed as a cell array rather than as a character vector. With a cell array you would have the option of passing line styles and line colors as well.

function abc(funs_cell, markers)
  funs = cellfun(@str2fun, funs_cell, 'uniform', 0);
  order = randperm(length(funs), 4);  %4 of them at random
  for K = order
      subplot(2,2, K)
      plot(x, funs{K}(x), markers{K});
      title(funs_cell{K});
  end
end

[Roger Nadal]

is it str2fun or str2func? and how to pass line colour using cell array?

[Walter Roberson]

Ah, str2func.

I was sure I had tested before; I must have transcribed it wrong when I posted.

abc({sin', 'sinh', 'cos', 'cosh'}, {'r-o', 'b-x', 'g-s', 'k--*'})

[Roger Nadal]

is there is any way to solve this without using any loop?and i want to pass markers argument and colours argument in vector with [ ] brace indexing

[Walter Roberson]

You could use [] indexing if you pass "" delimited string objects.

If you restrict to character vectors then when you use ['o', 'x', 's', '*'] then MATLAB cannot tell that apart from the case where you passed 'oxs*' as a single character vector. You would lose the flexibility of having specifications of different length. You could handle the case where the user always passed exactly the same number of characters per specification. For example you would not be able to specify dashed line with '--' unless the user always passed two characters for the line type even when they only wanted '-' or ':' line type.

[Roger Nadal]

And if I have to pass colour as third argument in function so should I just define it in function and plot it? abc({'sin','cos','tan','sinh'},['b','r','g','y'],['o','x','*','s']) so the first argument will be cell array and other two will be vector. and how to plot step 0.4 for each marker.

[Walter Roberson]

I don't know why you insist on not using a loop. I don't know why you insist on using character vectors for your markers and colors instead of the much more flexible cell array. But I no longer have patience to lead you through this, so I will give you what you are asking for, even though it is not what you should be using.

function abc(funs_cell, colors, markers)
    x = -2*pi:0.4:2*pi;

    order = randperm(length(funs),4);  %random order
    
    fun = str2fun(funs_cell{order(1)});
    subplot(2,2,1);
    plot(x, fun(x), 'LineStyle', '-', 'Color', colors(1), 'Marker', markers(1));
    title(funs_cell{order(1)});
    
    fun = str2fun(funs_cell{order(2)});
    subplot(2,2,2);
    plot(x, fun(x), 'LineStyle', '-', 'Color', colors(2), 'Marker', markers(2));
    title(funs_cell{order(2)});
    
    fun = str2fun(funs_cell{order(3)});
    subplot(2,2,3);
    plot(x, fun(x), 'LineStyle', '-', 'Color', colors(3), 'Marker', markers(3));
    title(funs_cell{order(3)});
    
    fun = str2fun(funs_cell{order(4)});
    subplot(2,2,4);
    plot(x, fun(x), 'LineStyle', '-', 'Color', colors(4), 'Marker', markers(4));
    title(funs_cell{order(4)});
end

[Roger Nadal]

funs is not define variable so is it fun or funs in length(funs)?

[Walter Roberson]

function abc(funs_cell, colors, markers)
    x = -2*pi:0.4:2*pi;
    order = randperm(length(funs_cell),4);  %random order
    
    fun = str2fun(funs_cell{order(1)});
    subplot(2,2,1);
    plot(x, fun(x), 'LineStyle', '-', 'Color', colors(1), 'Marker', markers(1));
    title(funs_cell{order(1)});
    
    fun = str2fun(funs_cell{order(2)});
    subplot(2,2,2);
    plot(x, fun(x), 'LineStyle', '-', 'Color', colors(2), 'Marker', markers(2));
    title(funs_cell{order(2)});
    
    fun = str2fun(funs_cell{order(3)});
    subplot(2,2,3);
    plot(x, fun(x), 'LineStyle', '-', 'Color', colors(3), 'Marker', markers(3));
    title(funs_cell{order(3)});
    
    fun = str2fun(funs_cell{order(4)});
    subplot(2,2,4);
    plot(x, fun(x), 'LineStyle', '-', 'Color', colors(4), 'Marker', markers(4));
    title(funs_cell{order(4)});
end

[Roger Nadal]

is there is any way to change points for x axes like in plot the points of x axes is [-5 5] instead i want [-10 10].

[Walter Roberson]

xlim([-10 10])

However you should be considering changing the definition of x instead. Your requirements were that it be -2*π to 2*π. Did that requirement change?

[Roger Nadal]

no the function should plot on interval [-2pi ,2pi] but the x axes i want [-10 10]. the order of plot is different than argument pass in fuction {sin', 'sinh', 'cos', 'cosh'} the plot order is sinh,cosh,sin,cos.

[Walter Roberson]

xlim controls the axes boundaries no matter what is plotted inside.

You asked for random order.

[Roger Nadal]

Ok got it.

[Roger Nadal]

if i am passing more than 4 input then it should output an error input vector length is different than 4 so how to put this condition in the program?

[Walter Roberson]

numels(variable) ~= 4

[Roger Nadal]

It can be done using if conditions?

[Walter Roberson]

if numels(funs_cell) ~= 4
    error('Opps, you did it again!')
end

[Roger Nadal]

It works for math function but if I am passing 5 values in market and colour it doesn’t work for that

[Walter Roberson]

Did you add similar tests for those variables?

[Roger Nadal]

It can’t be done in one condition?

[Walter Roberson]

You can combine three tests in a single if using the || operator.

This is a way to code it as a single if, but you would not be expected to work it out at the level of your homework assignment.

[Roger Nadal]

So I have to use 3 different if conditions?

[Walter Roberson]

if A || B || C
    error('Nada!')
end

[Roger Nadal]

Using this if i am passing 4 values then it also showing error

[Walter Roberson]

Please show your attempt.

[Roger Nadal]

If numel(fun_cell)||numel(color)~=4 Error(msg)

[Walter Roberson]

In MATLAB,

if numel(fun_cell)||numel(color)~=4 Error(msg)

would be interpreted as

if (numel(fun_cell) ~= 0) || (numel(color) ~= 4)
    error(msg)
end

MATLAB itself has absolutely no transitive operators of the form

expression1 operator1 expression2 operator2 value 

being intepreted as

(expression1 operator2 value) operator1 (expression2 operator2 value)

In MATLAB you need to be explicit,

if numel(fun_cell) ~= 4 || numel(color) ~= 4
    error(msg)
end

[Roger Nadal]

Thank you

[Roger Nadal]

If I don’t want to generate random order for then should I remove randperm?