Function by_name 

pub fn by_name<S, I>(names: I, strict: bool, expand_patterns: bool) -> Selector
where
    S: Into<PlSmallStr>,
    I: IntoIterator<Item = S>,

Select multiple columns by name.

When expand_patterns is true, a single wildcard "*" and anchored regex patterns (e.g. "^...$") are expanded to their matching columns. When false, names are treated as literals.