pht\Queue::front
(PECL pht >= 0.0.1)
pht\Queue::front — Returns the first value from a queue
Descrierea
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.
Parametri
Această funcție nu are parametri.
Valorile întoarse
The value on the front of the queue.
Exemple
Example #1 Retrieving the front value of a queue
<?php
use pht\Queue;
$queue = new Queue();
$queue->push(1);
var_dump($queue->front());
Exemplul de mai sus va afișa:
int(1)
Example #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
Example #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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