Question

I have this task:
sum all numbers in string and perform multiplication

input: "3 chairs, 2 tables, 2*3 forks"
result: 11

I already have regular expression to do this:

eval(str.match(/(\d[\d\.\*]*)/g).join(' + '))

But I want to add option to ignore numbers inside brackets “()”

input: "2 chairs, 3 tables (1 broke)"
result: 5

How to do it?

Regular expressions were always pain for me 🙁

Answer 1

One simple way is to do a first pass and remove all parenthesized expressions.

str = str.replace(/\([^\)]*\)/g, "");
// now run your original algorithm to sum/multiply...
// ...

This is not super efficient but it does the job.

I should note that this does not handle nested parentheses, but it doesn’t seem like that is required here.