How to convert string to number?

we have extracted a value from GUI using

id1=get(handles.id1,'String');

Now i want to check if the value is a number. How do i do this?

If the value is a number that is converted to a string using the above line, how do I convert it back to a number?

[KSSV]

Read about ischar, str2num, num2str,

Answer 1

[Stephen23]

"...how do I convert it back to a number?"

Convert to numeric:

num = str2double(id1)

"Now i want to check if the value is a number"

isn = ~isnan(num)