How to use float.Parse to get decimal from string like "5/2"

Question

If I had a string "5/2", how could I use float.Parse to get 2.5? When I do it inside Unity3D I get an Invalid Format error. It works for whole numbers, like "5" would get 5, but I'm making a graphing calculator and a lot of times the slope of line is a fraction.

Answer 1

It is not a valid number, it is an expression which needs to be evaluated. you can do that using DataTable.Compute. You can evaluate more complex expressions too using this technique.

var result = new DataTable().Compute("5/2",null);

Note: Datatable is expensive, so you can create a instance or static member which holds the reference of DataTable for you.

Read more about compute in MSDN.

Answer 2

You'll need to split the string, parse the values individually and then do the division. So :

string[] tokens = input.Split('/');
float result = float.Parse(tokens[0])/float.Parse(tokens[1]);

Of course, you should add error handling to this, but that is "Proof of Concept" quality code.