How to use str2func to replace eval command?

I want user to enter a parametrized function in terms of t. Is there a way that I can have an input function instead of using '' and eval?

t = linspace(0.001,2,1000);
T = t;
x_e = 't.^3';
y_e = 'exp(t)';
z_e = 'cos(10*t)';
x = eval(x_e);
y = eval(y_e);
z = eval(z_e);

Answer 1

[Walter Roberson]

fx = str2func(['@(t) ', x_e]);
x = fx(t);

Just like the examples in http://www.mathworks.com/help/matlab/ref/str2func.html

[Matthew]

I tried your way and it gave me an error

This is my code

t = linspace(0.001,2,1000);
T = t;
x_e = input ('x_e');
y_e = input ('y_e');
z_e = input ('z_e');
fx = str2func(['@(t) ', x_e], 't');
x = fx(t);
fy = str2func(['@(t) ', y_e], 't');
y = fy(t);
fz = str2func(['@(t) ', z_e], 't');
z = fz(t);

and this is what the command window said

Error using str2func
Too many input arguments.

Error in test (line 6)
fx = str2func(['@(t) ', x_e], 't');

Thx

[Walter Roberson]

Sorry, corrected. After I put in the bad code I checked the documentation and then forgot to fix the mistake before sending.

[Andrei Bobrov]

Hi Matthew and Walter!

t = linspace(0.001,2,1000);
x_e = 't.^3';
y_e = 'exp(t)';
z_e = 'cos(10*t)';
funs = cellfun(@str2func,strcat('@(t),{x_e,y_e,z_e}),'un',0);
rez = cellfun(@(q)q(t),funs,'un',0);
[x,y,z] = rez{:};

Answer 2

[Andrei Bobrov]

t = linspace(0.001,2,1000);
x_e = 't^3';
y_e = 'exp(t)';
z_e = 'cos(10*t)';

funs = arrayfun(@matlabFunction,sym({x_e,y_e,z_e}),'un',0);
rez = cellfun(@(q)q(t),funs,'un',0);
[x,y,z] = rez{:};

[Walter Roberson]

Notice here that Andrei had to change

x_e = 't.^3';

to

x_e = 't^3';

This is because sym() interprets strings as being in MuPAD language, which is slightly different than MATLAB itself. str2func() uses MATLAB language. matlabFunction() knows to convert MuPAD symbols into MATLAB language.

[Matthew]

Thanks I tried both of your ways and both of them work.