Make a Hashmap in Rust

get_from_hashmap.rs

use toml::Value;
use pad::{PadStr, Alignment};
use std::collections::BTreeMap;
use console::style;
fn main() {
    //toml_hash is a `BTreeMap<std::string::String, Vec<Value>>`
    let toml_hash: BTreeMap<String, Vec<toml::Value>> = toml::from_str(r#"
    foo = [1,nan,3]
    bar = ["a","b","c"]
    baz = [2021-03-29, 2020-03-29, 2020-03-29]
    barbaz = [1.0, 2.2, 3.3]
    "#).unwrap();
    //th is a        `BTreeMap<std::string::String, Vec<std::string::String>>`
    let value_types: BTreeMap<String, Vec<String>> = toml_hash
        .into_iter()
        .map(|(k, v)| (k, v.into_iter().map(|v| 
                 match v {
                     Value::String(_v)       => format!("<str>"),
                     Value::Integer(_v)      => format!("<int>"),
                     Value::Float(_v)        => format!("<dbl>"),
                     Value::Boolean(_v)      => format!("<lgl>"),
                     Value::Datetime(_v)     => format!("<dttm>"),
                     _                       => format!("None")})
             .collect()))
        .collect();
    let all_keys = value_types.keys().cloned().collect::<Vec<String>>();
    let first_values = value_types.values().filter_map(|vec| vec.first()).collect::<Vec<&String>>(); //first() give and Option<&Item>
    let max_value: Option<usize> = all_keys.iter().map(|x| x.len()).max();
    let names_with_white_space: Vec<_> = all_keys 
        .iter()
        .map(|x| x.pad_to_width_with_alignment(max_value.unwrap(), Alignment::Right))
        .collect();
    let types_with_white_space: Vec<_> = first_values
        .iter()
        .map(|x| x.pad_to_width_with_alignment(max_value.unwrap(), Alignment::Right))
        .collect();
    let title = names_with_white_space.join("  ");
    let types = types_with_white_space.join("  ");
    let left_margin = "\t";
    let title_formated:String = format!("{}{}",left_margin ,title);
    let types_formated:String = format!("{}{}",left_margin ,types);
    println!("{}",style(title_formated.clone()).bold());
    println!("{}",style(types_formated.clone()).bright().black());
    
}