PHP - Sequence Functions

Introduction to Sequence interface

A Sequence can describe the behavior of values arranged in a single, linear dimension. Some languages can refer to this as a List. It is similar to an array that uses incremental integer keys, with the exception of a few characteristics.

Values can always be indexed as [0, 1, 2, …, size - 1].
Only allowed to access values by index in the range [0, size - 1].

Use cases

Wherever we can use an array as a list (not concerned with keys).
A more efficient alternative to SplDoublyLinkedList and SplFixedArray.

Interface synopsis

Ds\Sequence implements Ds\Collection {
   /* Methods */
   abstract public void allocate( int $capacity )
   abstract public void apply( callable $callback )
   abstract public int capacity( void ) 
   abstract public bool contains([ mixed $...values ] )
   abstract public Ds\Sequence filter([ callable $callback ] )
   abstract public mixed find( mixed $value )
   abstract public mixed first( void )
   abstract public mixed get( int $index )
   abstract public void insert( int $index [, mixed $...values ] )
   abstract public string join([ string $glue ] )
   abstract public mixed last( void )
   abstract public Ds\Sequence map( callable $callback )
   abstract public Ds\Sequence merge( mixed $values )
   abstract public mixed pop( void )
   abstract public void push([ mixed $...values ] )
   abstract public mixed reduce( callable $callback [, mixed $initial ] )
   abstract public mixed remove( int $index )
   abstract public void reverse( void )
   abstract public Ds\Sequence reversed( void )
   abstract public void rotate( int $rotations )
   abstract public void set( int $index , mixed $value )
   abstract public mixed shift( void )
   abstract public Ds\Sequence slice( int $index [, int $length ] )
   abstract public void sort([ callable $comparator ] )
   abstract public Ds\Sequence sorted([ callable $comparator ] )
   abstract public number sum( void )
   abstract public void unshift([ mixed $values ] )
}

Predefined Constants

Ds\Map::MIN_CAPACITY

Sr.No	Function & Description
1	Ds\Sequence::allocate() This Function can allocate enough memory for a required capacity.
2	Ds\Sequence::apply() This Function can update all values by applying a callback function to each value.
3	Ds\Sequence::capacity() This Function can return the current capacity.
4	Ds\Sequence::contains() This Function can determine if a sequence contains given values.
5	Ds\Sequence::filter() create a new sequence using callable to determine which values to include.
6	Ds\Sequence::find() This Function can attempt to find the value's index.
7	Ds\Sequence::first() This Function can can return the first value in a sequence..
8	Ds\Sequence::get() This Function can return the value at a given index.
9	Ds\Sequence::insert() This Function can insert values at a given index.
10	Ds\Sequence::join() This Function can join all values together as a string.
11	Ds\Sequence::last() This Function can return the last value.
12	Ds\Sequence::map() This Function can return the result of applying a callback to each value.
13	Ds\Sequence::merge() This Function can return the result of adding all given values to the sequence.
14	Ds\Sequence::pop() This Function can remove and return the last value.
15	Ds\Sequence::push() This Function can add values to the end of a sequence.
16	Ds\Sequence::reduce() This Function can reduce the sequence to a single value using a callback function.
17	Ds\Sequence::remove() This Function can remove and return a value by index.
18	Ds\Sequence::reverse() This Function can can reverse a sequence in-place.
19	Ds\Sequence::reversed() This Function can return a reversed copy.
20	Ds\Sequence::rotate() This Function can rotate the sequence by given number of rotations.
21	Ds\Sequence::set() This Function can update a value at the given index.
22	Ds\Sequence::shift() This Function can remove and return a first value.
23	Ds\Sequence::slice() This Function can return a sub-sequence of the given range.
24	Ds\Sequence::sort() This Function can sort a sequence in-place.
25	Ds\Sequence::sorted() This Function can return a sorted copy.
26	Ds\Sequence::sum() This Function can return the sum of all values in a sequence.
27	Ds\Sequence::unshift() This Function add values to the front of a sequence.

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