Permutations class

A class representing permutations of items in a list.

This class is used to track and apply permutations of items, typically in the context of reordering elements within a list or grid.

Permutations are created by specifying the original and destination indices of an item, and they can be applied to a list to reflect the new order.

Example:

// Creating a Permutations instance
final permutations = Permutations();

// Adding a permutation to reorder an item from index 2 to index 5
permutations.addPermutation(
  itemKey: myItemKey,
  srcIndex: 2,
  destIndex: 5,
);

// Applying the permutations to a list
final myList = ['A', 'B', 'C', 'D', 'E'];
permutations.apply(myList);

In this example, the myList will be reordered based on the specified permutations.

The Permutations class keeps track of the mappings between original and new indices.

Inheritance

Constructors

Permutations.new()

Properties

first → Permutation
The first element.
no setterinherited
hashCode → int
The hash code for this object.
no setterinherited
isEmpty → bool
Returns true if there are no recorded permutations, indicating an empty state.
no setteroverride
isNotEmpty → bool
Whether this collection has at least one element.
no setterinherited
iterator → Iterator<Permutation>
A new Iterator that allows iterating the permutations.
no setteroverride
last → Permutation
The last element.
no setterinherited
length → int
The number of permutations.
no setteroverride
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
single → Permutation
Checks that this iterable has only one element, and returns that element.
no setterinherited

Methods

addPermutation({required Key itemKey, required int srcIndex, required int destIndex}) → void
Adds a permutation to the list.
any(bool test(Permutation element)) → bool
Checks whether any element of this iterable satisfies test.
inherited
apply<T>(List<T> list) → void
Applies the permutations to a provided list.
cast<R>() → Iterable<R>
A view of this iterable as an iterable of R instances.
inherited
contains(Object? element) → bool
Whether the collection contains an element equal to element.
inherited
elementAt(int index) → Permutation
Returns the indexth element.
inherited
every(bool test(Permutation element)) → bool
Checks whether every element of this iterable satisfies test.
inherited
expand<T>(Iterable<T> toElements(Permutation element)) → Iterable<T>
Expands each element of this Iterable into zero or more elements.
inherited
firstWhere(bool test(Permutation element), {Permutation orElse()?}) → Permutation
The first element that satisfies the given predicate test.
inherited
fold<T>(T initialValue, T combine(T previousValue, Permutation element)) → T
Reduces a collection to a single value by iteratively combining each element of the collection with an existing value
inherited
followedBy(Iterable<Permutation> other) → Iterable<Permutation>
Creates the lazy concatenation of this iterable and other.
inherited
forEach(void action(Permutation element)) → void
Invokes action on each element of this iterable in iteration order.
inherited
indexOf(Key itemKey) → int?
Returns the index of an item based on its key.
itemKeyAt(int index) → Key?
Returns the item key at a specified index.
join([String separator = ""]) → String
Converts each element to a String and concatenates the strings.
inherited
lastWhere(bool test(Permutation element), {Permutation orElse()?}) → Permutation
The last element that satisfies the given predicate test.
inherited
map<T>(T toElement(Permutation e)) → Iterable<T>
The current elements of this iterable modified by toElement.
inherited
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
reduce(Permutation combine(Permutation value, Permutation element)) → Permutation
Reduces a collection to a single value by iteratively combining elements of the collection using the provided function.
inherited
singleWhere(bool test(Permutation element), {Permutation orElse()?}) → Permutation
The single element that satisfies test.
inherited
skip(int count) → Iterable<Permutation>
Creates an Iterable that provides all but the first count elements.
inherited
skipWhile(bool test(Permutation value)) → Iterable<Permutation>
Creates an Iterable that skips leading elements while test is satisfied.
inherited
take(int count) → Iterable<Permutation>
Creates a lazy iterable of the count first elements of this iterable.
inherited
takeWhile(bool test(Permutation value)) → Iterable<Permutation>
Creates a lazy iterable of the leading elements satisfying test.
inherited
toList({bool growable = true}) → List<Permutation>
Creates a List containing the elements of this Iterable.
inherited
toSet() → Set<Permutation>
Creates a Set containing the same elements as this iterable.
inherited
toString() → String
Returns a string representation of (some of) the elements of this.
inherited
where(bool test(Permutation element)) → Iterable<Permutation>
Creates a new lazy Iterable with all elements that satisfy the predicate test.
inherited
whereType<T>() → Iterable<T>
Creates a new lazy Iterable with all elements that have type T.
inherited

Operators

operator ==(Object other) → bool
The equality operator.
inherited