How to manipulate data provided by a user via a dialog box?

Hi everyone --

I'm new to Matlab so excuse me if this is a simple question. I'm trying to write a program that allows a user to type in a single variable equation in a dialog box, a range for that equation, and an increment for that equation. The program then needs to generate a table and a plot of the equation.

I have my dialog box set up like this:

>> prompt = {'Enter your equation:','Enter minimum x:','Enter maximum x', 'Enter your increment:'};

>> name = 'Input for user''s function';

>> numLines = 1;

>> userInput = inputdlg(prompt,name,numLines);

As you can see I store the information in the cell userInput. How do I get the data out so that it's in a workable format? For example, I want to create a variable representing the whole range, like this:

>> range = userInput(2):userInput(3)

But Matlab gives me the error "Undefined function 'colon' for input arguments of type 'cell'."

I also want to plot the user's function like this:

>> plot(userInput(1))

But get the error "Error using plot. Conversions to double from cell is not possible."

So, how can I convert these user inputs into something I can work with? I am really stuck. Thank you for your help!

Answer 1

[Matt Fig]

With cell array you have to access the contents using curly braces. Also note that the data is a string, not a number.

range = str2double(userInput{2}):str2double(userInput{4}):str2double(userInput{3});
func = vectorize(inline(userInput{1}));
plot(range,func(range))

Answer 2

[Casey]

This did the trick, thank you!