Struct ingrid::RowMut

pub struct RowMut<'a, T> {
    pub grid: &'a mut Grid<T>,
    pub index: usize,
}

A mutable view onto a row of a grid

This structure is an mutable view into a row of a grid and its lifetime is bound to the lifetime of the grid. It's a lightweight construct that allows to operate on individual rows effectively; see it as an equivalent to the slice primitive for grids.

Instead of accessing elements with coordinates, just an index is needed. Rows use the left to right direction, therefore, index zero corresponds to the element at the very left, also denoted the 'first' element of the row. Note that rows are indexable.

With a row, you can easily retrieve the left and right elements of the row, with the left() and right() methods, but also retrieve the row above or below, with the top() and bottom() methods. You can also conveniently iterate over its elements with the iterator() method which returns an efficient iterator.

Unlike their immutable counter-part, there are additional operations you can do such as reversing the elements of the row, or rotate them to the left or the right.

Examples

Iterating over the elements of a row.

let mut grid = Grid::from_rows(vec![vec![1, 2, 3],
                                    vec![4, 5, 6]]);

let row = grid.row_mut(0);
for (coordinate, value) in row.iterator().enumerate_coordinate() {
    println!("Element at {:?} has value {}.", coordinate, *value);
}

Indexing the row.

let mut grid = Grid::from_rows(vec![vec![1, 2, 3],
                                    vec![4, 5, 6]]);

println!("First element of first row is {}", grid.row_mut(0)[0]);
println!("Last element of last row is {}", grid.row_mut(1)[2]);

Fields

grid: &'a mut Grid<T>

A reference to its grid.

index: usize

The index of the row.

Methods

impl<'a, T: Clone> RowMut<'a, T>

pub fn length(&self) -> usize

Returns the length of the row.

This method returns the length of the row which is the number of elements. It's equivalent to the width of the grid.

Examples

let mut grid = Grid::with_size(size!(3, 2), 42);

assert_eq!(grid.row_mut(0).length(), 3);
assert_eq!(grid.row_mut(1).length(), 3);
assert_eq!(grid.size().width, 3);

pub fn value(&self, index: usize) -> &T

Returns a reference to an element of the row.

This method returns a reference to an element of the row from its index.

Note that index zero corresponds to the element at the very left (the first element of the row). If you're looking to get the first or the last elements of the row, check out the left() and right() methods.

Arguments

• index - Index of the element

Panics

It panics if the index is out of bounds.

Examples

let mut grid = Grid::from_rows(vec![vec![1, 2, 3],
                                    vec![4, 5, 6]]);

let row = grid.row_mut(1);
assert_eq!(row.value(0), &4);
assert_eq!(row.value(1), &5);
assert_eq!(row.value(2), &6);
row.value(3); // It panics here !

pub fn value_mut(&mut self, index: usize) -> &mut T

Returns a mutable reference to an element of the row.

This method returns a mutable reference to an element of the row from its index.

Arguments

• index - Index of the element

Panics

It panics if the index is out of bounds.

Examples

let mut grid = Grid::from_rows(vec![vec![1, 2, 3],
                                    vec![4, 0, 6]]);

let mut row = grid.row_mut(1);
*row.value_mut(1) = 5;

assert_eq!(row.value(0), &4);
assert_eq!(row.value(1), &5);
assert_eq!(row.value(2), &6);

row.value(3); // It panics here !

pub fn set_value(&mut self, index: usize, value: T)

Replace an element of the row.

This method replaces the value of an element of the row from its index and a new value, effectively dropping the previous value.

Arguments

• index - Index of the element
• value - New value of the element

Panics

It panics if the index is out of bounds.

Examples

let mut grid = Grid::from_rows(vec![vec![1, 2, 3],
                                    vec![4, 0, 6]]);

let mut row = grid.row_mut(1);
row.set_value(1, 5);

assert_eq!(row.value(0), &4);
assert_eq!(row.value(1), &5);
assert_eq!(row.value(2), &6);

row.set_value(3, 42); // It panics here !

pub fn swap_value(&mut self, a: usize, b: usize)

Swap two elements of the row.

This method swaps two elements of the row from their index.

Arguments

• a - Index of one of the element to swap
• b - Index of the other element to be swapped with

Panics

It panics if the indexes are out of bounds.

Examples

let mut grid = Grid::from_rows(vec![vec![1, 2, 3],
                                    vec![6, 5, 4]]);

let mut row = grid.row_mut(1);
row.swap_value(0, 2);

assert_eq!(row.value(0), &4);
assert_eq!(row.value(1), &5);
assert_eq!(row.value(2), &6);

row.swap_value(1, 3); // It panics here !

pub fn values(&self) -> Vec<&T>

Return the elements of the row.

This method returns the elements of the row as a vector of reference.

Examples

let mut grid = Grid::from_rows(vec![vec![1, 2],
                                    vec![3, 4]]);

assert_eq!(grid.row_mut(0).values(), vec![&1, &2]);
assert_eq!(grid.row_mut(1).values(), vec![&3, &4]);

pub fn left(&self) -> &T

Returns a reference to the first element of the row.

This method returns a reference to the first element of the row. It's equivalent to retrieving the element with index 0.

Note that there is always a first element or the grid would have no size.

Examples

let mut grid = Grid::from_rows(vec![vec![1, 2, 3],
                                    vec![4, 5, 6]]);

// The first element of the second row is 4.
let row = grid.row_mut(1);
assert_eq!(row.left(), &4);

pub fn left_mut(&mut self) -> &mut T

Returns a mutable reference to the first element of the row.

This method returns a mutable reference to the first element of the row. It's equivalent to retrieving the element with index 0.

Note that there is always a first element or the grid would have no size.

Examples

let mut grid = Grid::from_rows(vec![vec![1, 2, 3],
                                    vec![0, 5, 6]]);

// The first element of the second row is 0 but we can change it to 4.
let mut row = grid.row_mut(1);
*row.left_mut() = 4;

assert_eq!(row.left(), &4);

pub fn right(&self) -> &T

Returns a reference to the last element of the row.

This method returns a reference to the last element of the row. It's equivalent to retrieving the element with index length() -1.

Note that there is always a last element or the grid would have no size.

Examples

let mut grid = Grid::from_rows(vec![vec![1, 2, 3],
                                    vec![4, 5, 6]]);

// The last element of the second row is 6.
let row = grid.row_mut(1);
assert_eq!(row.right(), &6);

pub fn right_mut(&mut self) -> &mut T

Returns a mutable reference to the last element of the row.

This method returns a mutable reference to the last element of the row. It's equivalent to retrieving the element with index length() -1.

Note that there is always a last element or the grid would have no size.

Examples

let mut grid = Grid::from_rows(vec![vec![1, 2, 3],
                                    vec![4, 5, 0]]);

// The last element of the second row is 0 but we can change it to 6.
let mut row = grid.row_mut(1);
*row.right_mut() = 6;

assert_eq!(row.right_mut(), &6);

Important traits for IteratorRow<'a, T>

impl<'a, T: Clone> Iterator for IteratorRow<'a, T> type Item = &'a T;

pub fn iterator(&'a self) -> IteratorRow<'a, T>

Returns an iterator over the row.

This method returns an iterator over the row.

Examples

let mut grid = Grid::from_rows(vec![vec![ 1,  2,  3],
                                    vec![42, 42, 42]]);

// Check if all elements of the row have value 42.
assert_eq!(grid.row_mut(0).iterator().all(|item| *item == 42), false);
assert_eq!(grid.row_mut(1).iterator().all(|item| *item == 42), true);

pub fn top(&'a self) -> Option<Row<'a, T>>

Returns the row above.

This method returns the row above this row, or None if this is already the row at the very top of the grid.

Examples

let mut grid = Grid::from_rows(vec![vec![1, 2],
                                    vec![3, 4]]);

let second_row = grid.row_mut(1);
let first_row = second_row.top().unwrap();
assert!(first_row.top().is_none()); // There is no row above.

pub fn top_mut(&'a mut self) -> Option<RowMut<'a, T>>

Returns the mutable row above.

This method returns the mutable row above this row, or None if this is already the row at the very top of the grid.

Examples

let mut grid = Grid::from_rows(vec![vec![1, 2],
                                    vec![3, 4]]);

let mut second_row = grid.row_mut(1);
let mut first_row = second_row.top_mut().unwrap();
assert!(first_row.top_mut().is_none()); // There is no row above.

pub fn bottom(&'a self) -> Option<Row<'a, T>>

Returns the row below.

This method returns the row below this row, or None if this is already the row at the very bottom of the grid.

Examples

let mut grid = Grid::from_rows(vec![vec![1, 2],
                                    vec![3, 4]]);

let mut first_row = grid.row_mut(0);
let second_row = first_row.bottom().unwrap();
assert!(second_row.bottom().is_none()); // There is no row below.

pub fn bottom_mut(&'a mut self) -> Option<RowMut<'a, T>>

Returns the mutable row below.

This method returns the mutable row below this row, or None if this is already the row at the very bottom of the grid.

Examples

let mut grid = Grid::from_rows(vec![vec![1, 2],
                                    vec![3, 4]]);

let mut first_row = grid.row_mut(0);
let mut second_row = first_row.bottom_mut().unwrap();
assert!(second_row.bottom_mut().is_none()); // There is no row below.

pub fn reverse(&mut self)

Reverse the order of the elements.

This method reverses the order of the elements in the row, in place.

Note that it's similar to the reverse() method of the slice primitive type.

Examples

let mut grid = Grid::from_rows(vec![vec![1, 2, 3],
                                    vec![6, 5, 4]]);

let mut row = grid.row_mut(1);
row.reverse();

assert_eq!(row.value(0), &4);
assert_eq!(row.value(1), &5);
assert_eq!(row.value(2), &6);

pub fn rotate_left(&mut self, number: usize)

Rotate elements to the left.

This method rotates the row in-place such that the elements are moved a given number of times to the left. The elements that goes out of the row are added back to the right of the row.

Note that it's similar to the rotate_left() method of the slice primitive type.

Arguments

• number - The number of times elements are rotated

Panics

This function will panic if number is greater than the length of the row.

Examples

let mut grid = Grid::from_rows(vec![vec![1, 2, 3],
                                    vec![4, 5, 6]]);

let mut row = grid.row_mut(1);
row.rotate_left(1);

assert_eq!(row.value(0), &5);
assert_eq!(row.value(1), &6);
assert_eq!(row.value(2), &4);

pub fn rotate_right(&mut self, number: usize)

Rotate elements to the right.

This method rotates the row in-place such that the elements are moved a given number of times to the right. The elements that goes out of the row are added back to the left of the row.

Note that it's similar to the rotate_right() method of the slice primitive type.

Arguments

• number - The number of times elements are rotated

Panics

This function will panic if number is greater than the length of the row.

Examples

let mut grid = Grid::from_rows(vec![vec![1, 2, 3],
                                    vec![4, 5, 6]]);

let mut row = grid.row_mut(1);
row.rotate_right(1);

assert_eq!(row.value(0), &6);
assert_eq!(row.value(1), &4);
assert_eq!(row.value(2), &5);

pub fn swap(&mut self, a: usize, b: usize)

Swap two elements in the row.

This method swaps two elements in the row.

Note that it's similar to the swap() method of the slice primitive type.

Arguments

• a - The index of the first element
• b - The index of the second element

Panics

It panics if a or b are out of bounds.

Examples

let mut grid = Grid::from_rows(vec![vec![1, 2, 3],
                                    vec![6, 5, 4]]);

let mut row = grid.row_mut(1);
row.swap(0, 2);

assert_eq!(row.value(0), &4);
assert_eq!(row.value(1), &5);
assert_eq!(row.value(2), &6);

Trait Implementations

impl<'a, T: Debug> Debug for RowMut<'a, T>

fn fmt(&self, f: &mut Formatter) -> Result

Formats the value using the given formatter.

impl<'a, T: Eq> Eq for RowMut<'a, T>

impl<'a, T: Clone> Index<usize> for RowMut<'a, T>

type Output = T

The returned type after indexing.

fn index(&self, index: usize) -> &Self::Output

Performs the indexing (container[index]) operation.

impl<'a, T: Clone> IndexMut<usize> for RowMut<'a, T>

fn index_mut(&mut self, index: usize) -> &mut Self::Output

Performs the mutable indexing (container[index]) operation.

impl<'a, T: PartialEq> PartialEq<RowMut<'a, T>> for RowMut<'a, T>

fn eq(&self, other: &RowMut<'a, T>) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &RowMut<'a, T>) -> bool

This method tests for !=.

impl<'a, T> StructuralEq for RowMut<'a, T>

impl<'a, T> StructuralPartialEq for RowMut<'a, T>