// Copyright 2014-2016 bluss and ndarray developers.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
//! Methods for two-dimensional arrays.
use crate::imp_prelude::*;
/// # Methods For 2-D Arrays
impl<A, S> ArrayBase<S, Ix2>
where
S: RawData<Elem = A>,
{
/// Return an array view of row `index`.
///
/// **Panics** if `index` is out of bounds.
///
/// ```
/// use ndarray::array;
/// let array = array![[1., 2.], [3., 4.]];
/// assert_eq!(array.row(0), array![1., 2.]);
/// ```
pub fn row(&self, index: Ix) -> ArrayView1<'_, A>
where
S: Data,
{
self.index_axis(Axis(0), index)
}
/// Return a mutable array view of row `index`.
///
/// **Panics** if `index` is out of bounds.
///
/// ```
/// use ndarray::array;
/// let mut array = array![[1., 2.], [3., 4.]];
/// array.row_mut(0)[1] = 5.;
/// assert_eq!(array, array![[1., 5.], [3., 4.]]);
/// ```
pub fn row_mut(&mut self, index: Ix) -> ArrayViewMut1<'_, A>
where
S: DataMut,
{
self.index_axis_mut(Axis(0), index)
}
/// Return the number of rows (length of `Axis(0)`) in the two-dimensional array.
///
/// ```
/// use ndarray::array;
/// let array = array![[1., 2.], [3., 4.]];
/// assert_eq!(array.nrows(), 2usize);
/// ```
pub fn nrows(&self) -> usize {
self.len_of(Axis(0))
}
/// Return an array view of column `index`.
///
/// **Panics** if `index` is out of bounds.
///
/// ```
/// use ndarray::array;
/// let array = array![[1., 2.], [3., 4.]];
/// assert_eq!(array.column(0), array![1., 3.]);
/// ```
pub fn column(&self, index: Ix) -> ArrayView1<'_, A>
where
S: Data,
{
self.index_axis(Axis(1), index)
}
/// Return a mutable array view of column `index`.
///
/// **Panics** if `index` is out of bounds.
///
/// ```
/// use ndarray::array;
/// let mut array = array![[1., 2.], [3., 4.]];
/// array.column_mut(0)[1] = 5.;
/// assert_eq!(array, array![[1., 2.], [5., 4.]]);
/// ```
pub fn column_mut(&mut self, index: Ix) -> ArrayViewMut1<'_, A>
where
S: DataMut,
{
self.index_axis_mut(Axis(1), index)
}
/// Return the number of columns (length of `Axis(1)`) in the two-dimensional array.
///
/// ```
/// use ndarray::array;
/// let array = array![[1., 2.], [3., 4.]];
/// assert_eq!(array.ncols(), 2usize);
/// ```
pub fn ncols(&self) -> usize {
self.len_of(Axis(1))
}
/// Return true if the array is square, false otherwise.
///
/// # Examples
/// Sqaure:
/// ```
/// use ndarray::array;
/// let array = array![[1., 2.], [3., 4.]];
/// assert!(array.is_square());
/// ```
/// Not sqaure:
/// ```
/// use ndarray::array;
/// let array = array![[1., 2., 5.], [3., 4., 6.]];
/// assert!(!array.is_square());
/// ```
pub fn is_square(&self) -> bool {
let (m, n) = self.dim();
m == n
}
}