How Can I Evaluate Mathematical Expressions from Strings in Java?

Evaluate Mathematical Expressions from Strings in Java

Parsing mathematical expressions from strings into meaningful numeric results is a common task in programming. In Java, several approaches can be employed to achieve this.

BeanShell Interpreter

One convenient option is to leverage the BeanShell scripting engine. It provides a lightweight and embedded interpreter that enables the evaluation of expressions dynamically. To use it:

Interpreter interpreter = new Interpreter();
interpreter.eval("result = 5+4*(7-15)");
System.out.println(interpreter.get("result"));

ANTLR

For more complex parsing requirements, ANTLR (ANother Tool for Language Recognition) can be utilized. It is a parsing framework that allows you to define your own grammar and generate parsers and lexers for different languages. ANTLR likely provides a pre-built grammar for mathematical expressions, making the parsing process simpler.

By following these approaches, you can effectively parse mathematical expressions from strings and obtain their evaluated results in Java.

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