How do I use RegEx to leave numbers and math operators inside of parenthesis-CodePudding

Using Javascript and RegEx, how I can start with something like this...

((5 dogs   2 cats) * $3.00 per animal)   $20 flat fee

...and end up with just the math operators (allowing for both x and * for multiplication), dollar signs, decimal points, spaces and numbers...

(5   2) * $3.00)   $20

Ideally, there would be two levels of nesting max; but if that's not possible, one level would also be useful.

CodePudding user response：

You could use a string replace using a regular expression matching only symbols different from the allowed characters: -*/[0-9].$() to be replaced with empty string.

Here's a demo:

const formula = "((5 dogs   2 cats) * $3.00 per animal)   $20 flat fee";
const result = formula.replace(/[^- *\/()\d.$]/img, "");

console.log(result);

CodePudding user response：

Something you can do is to remove the characters you don't want from the string (a-z, double spaces...).

At least for your example seems to work.