pub fn exchange_prefix(code: &str) -> &str {
if code.starts_with('6') {
"sh"
} else {
"sz"
}
}
pub fn format_stock_code(codes: Vec<&str>) -> Vec<String> {
if !codes.is_empty() && codes[0].starts_with('s') {
return codes.iter().map(|x| x.to_string()).collect();
}
let mut res = Vec::with_capacity(codes.len());
for code in codes.iter() {
res.push(format!("{}{}", exchange_prefix(&code), code));
}
res
}