Function atomic_mass_by_symbol 

pub fn atomic_mass_by_symbol(symbol: &str) -> Option<f64>

Looks up the average atomic mass for an element symbol.

Examples

use use_atomic_mass::atomic_mass_by_symbol;

assert!((atomic_mass_by_symbol("C").unwrap() - 12.011).abs() < 0.01);
assert!(atomic_mass_by_symbol("??").is_none());