Vertical and Horizontal stacking

stack_df.rs

pub fn deal_with_stacks<P: AsRef<Path>>(path: P) -> () {
    /* Stack, often happens to stack multiple dataframes together*/
    println!("Read the same dataframe twice");
    let df = read_csv(&path).unwrap();
    let df2 = read_csv(&path).unwrap();
    println!("Vertical stack the two dataframes");
    let mut df3 = df.vstack(&df2).unwrap(); // mut --> so we can change this dataframe later
    println!("{}, {:#?}", df3.head(Some(5)), df3.shape());
    // get column 
    println!("Get a column");
    let  sepal_length = df3.column("sepal.length").unwrap();
    println!("{}", sepal_length);
    println!("{:#?}", sepal_length.len());
    // drop columns
    println!("Drop a column");
    let sepal_length = df3.drop_in_place("sepal.length").unwrap(); // inplace
    // this commands return a Series
    println!("{}", df3.head(Some(5)));
    // drop_nulls() to drop NaN
    //let df4 = df3.drop("sepal.length"); // if we don't want a mut dataframe df3
    println!("Insert a series in a dataframe as a new column");
    let _df4 = df3.insert_at_idx(0, sepal_length).unwrap();
    println!("{}", _df4.head(Some(5)));

}