CODEWITHSUNDEEP
matlab
Dani Grosu
Dani Grosu

Reputation: 554

Matlab: From 'edit' (textbox input) to mathematical expression

I have a uicontrol of type 'edit' and I want to be able to write something like sin(2*10*pi*t)-sin(2*15*pi*t) on it and then this string to become an expression for a variable F, for example: F=sin(2*10*pi*t)-sin(2*15*pi*t); where t is previously declared.

string=get(uicontrol_data, 'String');
%now I have the string value of the input

What should I do in order to transform the string into an expression?

Upvotes: 0

Views: 117

Answers (2)

Luis Mendo
Luis Mendo

Reputation: 112769

You can avoid using eval (which is generally not recommended) by means of str2func:

str = get(uicontrol_data, 'String'); %// reads string grom uicontrol
f = str2func(['@(t)' str]);  %// creates anonymous function and function handle
F = f(t); %// evaluates that function for the previously declared variable `t`

Upvotes: 1

LowPolyCorgi
LowPolyCorgi

Reputation: 5188

You have to use the built-in eval function. For instance:

string = get(uicontrol_data, 'String');
eval(['F = ' string ';']);   % Equivalent of F = ...;

Best,

Upvotes: 0

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