use oxyroot::RootFile;
fn main() {
let tree = RootFile::open("o.root").unwrap().get_tree("T").unwrap();
let e_beam_iter = tree.branch("v_i").unwrap().as_iter::<f32>().unwrap();
let data: Vec<f32> = e_beam_iter.collect(); let sum: f32 = data.iter().sum();
println!("{}", sum / data.len() as f32);
}