make sorted string

gistfile1.rs

use std::fmt::Write;

use polars::prelude::*;

fn make_sorted_array_series(input: Vec<String>, datatype: &DataType) -> Vec<String> {
    input
        .into_iter()
        .map(|s| {
            let splited = s.split(",");

            match datatype {
                DataType::Int32 => {
                    let mut item_vec = splited
                        .map(|e| e.parse::<i32>().unwrap())
                        .collect::<Vec<_>>();

                    item_vec.sort();

                    let mut new_s = item_vec.into_iter().fold(String::with_capacity(s.len()), |mut a, b| {
                        write!(&mut a, "{},", b).unwrap();
                        a
                    });

                    new_s.pop().unwrap();
                    new_s
                }
                _ => todo!(),
            }
        })
        .collect::<Vec<_>>()
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_sorted_element_of_vec() {
        let a = [
            "123,456,789,1,-1,0,22,-345",
            "123,456",
            "123,0,22,-345",
            "123,456,789,-345",
        ].into_iter().map(ToString::to_string).collect::<Vec<_>>();
        
        let answer = [
            "-345,-1,0,1,22,123,456,789",
            "123,456",
            "-345,0,22,123",
            "-345,123,456,789",
        ].into_iter().map(ToString::to_string).collect::<Vec<_>>();

        assert_eq!(answer,make_sorted_array_series(a, &DataType::Int32));
    }
}