Parsing a chemical formula

Question

I\'m trying to write a method for an app that takes a chemical formula like \"CH3COOH\" and returns some sort of collection full of their symbols.

CH3COOH would retu

Answer 1

Assuming it's correctly capitalised, each symbol in the equation matches this regular expression:

[A-Z][a-z]*\d*

(For the chemically challenged, an element's symbol is always capital letter followed by optionally a lower case one or possibly two - e.g. Hg for mercury)

You can capture the element symbol and the number in groups like so:

([A-Z][a-z]*)(\d*)

So yes, in theory this would be something regular expressions could help with. If you're dealing with formulae like C₆H₂(NO₂)₃(CH₃)₃ then your job is of course a bit harder...