pub fn at(&self, i: usize) -> Scalar {
        dtype_match!(self.dtype, self.at_raw(i), Scalar::new)
    }
Getter for Series

# Examples

```rust
extern crate peroxide;
use peroxide::fuga::*;

fn main() {
let a = Series::new(vec![1i32,2,3,4]);
let x = a.at(0);

assert_eq!(x, Scalar::new(1i32));
}
```
src/structure/dataframe.rs