pht\Queue::front
(PECL pht >= 0.0.1)
pht\Queue::front — Returns the first value from a queue
Beschreibung
This method will remove a value from the front of the queue (in constant time). Attempting to return the front value from an empty queue will result in an Error exception.
Due to the fact that all values in a pht\Queue are serialised, extracting a value from the queue will require it to be deserialised. This can incur a noticeable performance hit if the inspection of the queue's front value is performed within a loop.
Parameter-Liste
Diese Funktion besitzt keine Parameter.
Rückgabewerte
The value on the front of the queue.
Beispiele
Beispiel #1 Retrieving the front value of a queue
<?php
use pht\Queue;
$queue = new Queue();
$queue->push(1);
var_dump($queue->front());
Das oben gezeigte Beispiel erzeugt folgende Ausgabe:
int(1)
Beispiel #2 Retrieving the front value in a loop (bad example - don't do this)
<?php
use pht\Queue;
$queue = new Queue();
$queue->push(array_fill(0, 2000, 0));
for ($i = 0; $i < count($queue->front()); ++$i); // quadratic runtime
Beispiel #3 Retrieving the front value in a loop (good example)
<?php
use pht\Queue;
$queue = new Queue();
$queue->push(array_fill(0, 2000, 0));
$front = $queue->front(); // create a separate variable
for ($i = 0; $i < count($front); ++$i); // linear runtime
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