Convert a symbolic expression to string

I haVE A SYMBOLIC EXPRESSION WHICHI WANT TO USE AS A STRING EXPRESSION WITHOUT EVALUATING IT. EXAMPLE IF I HAVE

A=9

B=5

IF WE WRITE STRING(A+B-(A*B) ) WE GET ANSWER -31

BUT I WANT 9+5-(9*5) . HOW TO DO IT

Answer 1

[madhan ravi]

https://www.mathworks.com/matlabcentral/answers/312339-how-to-convert-strings-to-symbolic-expressions-without-sym#answer_243406

https://www.mathworks.com/matlabcentral/answers/68530-how-to-convert-a-string-to-a-symbol#answer_79951

Answer 2

[Walter Roberson]

https://www.mathworks.com/help/matlab/ref/compose.html

As you appear to want to use string objects use compose()

[Walter Roberson]

Since R2019b, you can do

A=9

A = 9

B=5

B = 5

displayFormula('A+B-(A*B)')

Notice that the () disappeared though.

[Walter Roberson]

A = 9; B = 5;
str = 'A+B-(A*B)/GRAB'

str = 'A+B-(A*B)/GRAB'

regexprep(str, {'\<A\>', '\<B\>'}, {num2str(A), num2str(B)})

ans = '9+5-(9*5)/GRAB'

The \< and \> are there to force it to replace only when the names are the entire "word" -- the A and B inside of GRAB should not be replaced

Answer 3

[Rajan Prasad]

Use string() command. This will convert the symbolic expression into string and then you can export into any format.

[Walter Roberson]

That will not work to prevent evaluation of the expression while still substituting in values of the variables.

[Rajan Prasad]

The string command will convert the symbolic expression into string. Instead of typing/entering the symbolic expression agian, one can use string. Then can use regexprep as suggested by you to replace the desired string to get in the string format with value.