PHP | Ds\Deque first() Function Last Updated : 14 Aug, 2019 Summarize Comments Improve Suggest changes Share Like Article Like Report The Ds\Deque::first() function is an inbuilt function in PHP which returns the first value in the Deque if Deque is not empty. Syntax: public Ds\Deque::first( void ) : mixed Parameters: This function does not accept any parameter. Return Value: This function returns the first element from the Deque, if the deque is not empty. Below programs illustrate the Ds\Deque::first() function in PHP: Program 1: PHP <?php // Declare a deque $deck = new \Ds\Deque([10, 20, 3, 40, 50, 6]); echo("Elements in the Deque\n"); // Display the Deque elements print_r($deck); echo("\nFirst element in the deque: "); // Use first() function to find // first element in the deque var_dump($deck->first()); ?> Output: Elements in the Deque Ds\Deque Object ( [0] => 10 [1] => 20 [2] => 3 [3] => 40 [4] => 50 [5] => 6 ) First element in the deque: int(10) Program 2: PHP <?php // Declare a deque $deck = new \Ds\Deque(["Geeks", "for", "GFG"]); echo("Elements in the Deque\n"); // Display the Deque elements print_r($deck); echo("\nFirst element in the deque: "); // Use first() function to find // first element in the deque var_dump($deck->first()); ?> Output: Elements in the Deque Ds\Deque Object ( [0] => Geeks [1] => for [2] => GFG ) First element in the deque: string(5) "Geeks" Reference: http://php.net/manual/en/ds-deque.first.php Comment More infoAdvertise with us Next Article PHP | DsSequence first() Function B barykrg Follow Improve Article Tags : Web Technologies PHP PHP-function Similar Reads PHP | DsDeque first() Function The Ds\Deque::first() function is an inbuilt function in PHP which returns the first value in the Deque if Deque is not empty. Syntax: public Ds\Deque::first( void ) : mixed Parameters: This function does not accept any parameter. Return Value: This function returns the first element from the Deque, 2 min read PHP | DsSequence first() Function The Ds\Sequence::first() function is an inbuilt function in PHP which is used to return the first element from the sequence. Syntax: mixed abstract public Ds\Sequence::first ( void ) Parameter: This function does not accepts any parameter. Return value: This function returns the first element from t 1 min read PHP | DsSet first() Function The Ds\Set::first() function is an inbuilt function in PHP which returns the first element of the Set. Syntax: void public Ds\Set::first( void ) Parameter: This function does not accept any parameter. Return value: This function returns the first value of the Set. Below programs illustrate the Ds\Se 1 min read PHP | DsDeque filter() Function The Ds\Deque::filter() function is an inbuilt function in PHP which is used to filter out the elements from the deque based on the operation defined in the callback function. Syntax: public Ds\Deque::filter( $callback ) : Ds\Deque Parameters: This function accepts single parameter $callback which is 2 min read PHP | DsDeque find() Function The Ds\Deque::find() function is an inbuilt function in PHP which is used to find the index of the element in the Deque if element found in the Deque.Syntax: public Ds\Deque::find( $value ) : mixed Parameters: This function accepts single parameter $value which holds the element whose index is to be 2 min read PHP | DsVector first() Function The Ds\Vector::first() function is an inbuilt function in PHP which is used to find the first element in the vector. Syntax: mixed public Ds\Vector::first( void ) Parameters: This function does not accept any parameter. Return Value: This function returns the first element present in the vector. Bel 1 min read PHP | Ds\Deque first() Function min read Like