ndarray/impl_2d.rs
1// Copyright 2014-2016 bluss and ndarray developers.
2//
3// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
4// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
5// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
6// option. This file may not be copied, modified, or distributed
7// except according to those terms.
8
9//! Methods for two-dimensional arrays.
10use crate::imp_prelude::*;
11
12/// # Methods For 2-D Arrays
13impl<A, S> ArrayBase<S, Ix2>
14where S: RawData<Elem = A>
15{
16 /// Return an array view of row `index`.
17 ///
18 /// **Panics** if `index` is out of bounds.
19 ///
20 /// ```
21 /// use ndarray::array;
22 /// let array = array![[1., 2.], [3., 4.]];
23 /// assert_eq!(array.row(0), array![1., 2.]);
24 /// ```
25 #[track_caller]
26 pub fn row(&self, index: Ix) -> ArrayView1<'_, A>
27 where S: Data
28 {
29 self.index_axis(Axis(0), index)
30 }
31
32 /// Return a mutable array view of row `index`.
33 ///
34 /// **Panics** if `index` is out of bounds.
35 ///
36 /// ```
37 /// use ndarray::array;
38 /// let mut array = array![[1., 2.], [3., 4.]];
39 /// array.row_mut(0)[1] = 5.;
40 /// assert_eq!(array, array![[1., 5.], [3., 4.]]);
41 /// ```
42 #[track_caller]
43 pub fn row_mut(&mut self, index: Ix) -> ArrayViewMut1<'_, A>
44 where S: DataMut
45 {
46 self.index_axis_mut(Axis(0), index)
47 }
48
49 /// Return the number of rows (length of `Axis(0)`) in the two-dimensional array.
50 ///
51 /// ```
52 /// use ndarray::{array, Axis};
53 ///
54 /// let array = array![[1., 2.],
55 /// [3., 4.],
56 /// [5., 6.]];
57 /// assert_eq!(array.nrows(), 3);
58 ///
59 /// // equivalent ways of getting the dimensions
60 /// // get nrows, ncols by using dim:
61 /// let (m, n) = array.dim();
62 /// assert_eq!(m, array.nrows());
63 /// // get length of any particular axis with .len_of()
64 /// assert_eq!(m, array.len_of(Axis(0)));
65 /// ```
66 pub fn nrows(&self) -> usize
67 {
68 self.len_of(Axis(0))
69 }
70
71 /// Return an array view of column `index`.
72 ///
73 /// **Panics** if `index` is out of bounds.
74 ///
75 /// ```
76 /// use ndarray::array;
77 /// let array = array![[1., 2.], [3., 4.]];
78 /// assert_eq!(array.column(0), array![1., 3.]);
79 /// ```
80 #[track_caller]
81 pub fn column(&self, index: Ix) -> ArrayView1<'_, A>
82 where S: Data
83 {
84 self.index_axis(Axis(1), index)
85 }
86
87 /// Return a mutable array view of column `index`.
88 ///
89 /// **Panics** if `index` is out of bounds.
90 ///
91 /// ```
92 /// use ndarray::array;
93 /// let mut array = array![[1., 2.], [3., 4.]];
94 /// array.column_mut(0)[1] = 5.;
95 /// assert_eq!(array, array![[1., 2.], [5., 4.]]);
96 /// ```
97 #[track_caller]
98 pub fn column_mut(&mut self, index: Ix) -> ArrayViewMut1<'_, A>
99 where S: DataMut
100 {
101 self.index_axis_mut(Axis(1), index)
102 }
103
104 /// Return the number of columns (length of `Axis(1)`) in the two-dimensional array.
105 ///
106 /// ```
107 /// use ndarray::{array, Axis};
108 ///
109 /// let array = array![[1., 2.],
110 /// [3., 4.],
111 /// [5., 6.]];
112 /// assert_eq!(array.ncols(), 2);
113 ///
114 /// // equivalent ways of getting the dimensions
115 /// // get nrows, ncols by using dim:
116 /// let (m, n) = array.dim();
117 /// assert_eq!(n, array.ncols());
118 /// // get length of any particular axis with .len_of()
119 /// assert_eq!(n, array.len_of(Axis(1)));
120 /// ```
121 pub fn ncols(&self) -> usize
122 {
123 self.len_of(Axis(1))
124 }
125
126 /// Return true if the array is square, false otherwise.
127 ///
128 /// # Examples
129 /// Square:
130 /// ```
131 /// use ndarray::array;
132 /// let array = array![[1., 2.], [3., 4.]];
133 /// assert!(array.is_square());
134 /// ```
135 /// Not square:
136 /// ```
137 /// use ndarray::array;
138 /// let array = array![[1., 2., 5.], [3., 4., 6.]];
139 /// assert!(!array.is_square());
140 /// ```
141 pub fn is_square(&self) -> bool
142 {
143 let (m, n) = self.dim();
144 m == n
145 }
146}