transform to input to symbol

Dear all

how can i creat a function which take any desired variable like x or y or z and transform it to a symbol. i mean the function take the x and give back to symbol x.

thanks alot

Answer 1

[madhan ravi]

syms(sym('x')) % works only for scalar variables , bearing in mind this is only used for symbolic calculations.

https://in.mathworks.com/matlabcentral/answers/427731-how-can-i-generate-a-matrix-of-symbolic-functions-whose-size-varies-depending-on-the-input-values#answer_344949

[saeed rezaei]

thanks for your helping

let me explain my problem exactly with another example.

suppose that we created a function ( saeed function) which takes an expression and a number. then calculates the expression based on the number and gives back the result. for example:

>>saeed(x^2+x-5,2)

ans:

1

the function is like this

function [out]=saeed(eq,n)

the problem is that when user enter this : saeed(x^2+x-5,2) the matlab gives an error. the error is:

Undefined function or variable 'x'.

as you know we can define x as a symbol. but we can do this befor function. now, what should i do ?

[madhan ravi]

saeed?? Upload the function.

[saeed rezaei]

saeed is a desirable name. its my name :)

function [out]=saeed(eq,n)

clc

clear all

eqn=eq(n)

end

[madhan ravi]

eq=input('Enter the equation:','s') % Type x^2+x-5
n=2;
eqn = str2func(['@(x)',eq]);
eqn(n)

Note: Remove clc and clear all inside your function.

[saeed rezaei]

yeah

i know this way. but this code is not a function.

i wanna write the code as a function so that the user can enter saeed(eq,n) and take back the answer

[madhan ravi]

eq=input('Enter the equation:','s') % Type x^2+x-5
n=2;
Result = saeed(eq,n)

function Result=saeed(eq,n)
eqn = str2func(['@(x)',eq]);
Result=eqn(n);
end