Split a mathematical expression

Question

I'm separating a string which is a mathematical expression, I want to split every number, operator and parentheses, and send them to an array, this is my code:

Scanner in = new Scanner(System.in);
System.out.println("enter the expression :");
String infija = in.nextLine();
String separate[] = infix.split("(?=[-+*/%()])|(?<=[^-+*/%][-+*/])|(?<=[()])");

but when I enter an expression with m modulus, the code does not separate it.

For example, entering

(2/3)+(2%1)

the expected result is:

[(,2, /, 3,), +,(, 2, %, 1,)] 

Answer 1

There's an easier way:

String separate[] = infix.split("\\b|(?<=\\D)(?=\\D)");

This splits on word boundary and between non-digits.

In regex, a "word" char is any digit, letter or underscore. A word boundary is between a word char and a non-word char (and visa versa).

---

Test code:

 System.out.println(Arrays.toString("2/(3+2)%1".split("\\b|(?<=\\D)(?=\\D)")));

output:

[2, /, (, 3, +, 2, ), %, 1]

Answer 2

This should do it,

    String myString= "(2/3)+(2%1)";
    String[] result = myString.split("(?<=[-+*/%()])|(?=[-+*/%()])");
    System.out.println(Arrays.toString(result));

output:

    [(, 2, /, 3, ), +, (, 2, %, 1, )]