The SplFixedArray class

The SplFixedArray class provides the main functionalities of array. The main differences between a SplFixedArray and a normal PHP array is that the SplFixedArray is of fixed length and allows only integers within the range as indexes. The advantage is that it allows a faster array implementation.

类摘要

SplFixedArray implements Iterator , ArrayAccess , Countable {
/* 方法 */
public __construct ([ int $size = 0 ] )
public int count ( void )
public mixed current ( void )
public static SplFixedArray fromArray ( array $array [, bool $save_indexes = true ] )
public int getSize ( void )
public int key ( void )
public void next ( void )
public bool offsetExists ( int $index )
public mixed offsetGet ( int $index )
public void offsetSet ( int $index , mixed $newval )
public void offsetUnset ( int $index )
public void rewind ( void )
public int setSize ( int $size )
public array toArray ( void )
public bool valid ( void )
public void __wakeup ( void )
}

 

范例

Example #1 SplFixedArray usage example

<?php
// Initialize the array with a fixed length
$array = new SplFixedArray(5);

$array[1] = 2;
$array[4] = "foo";

var_dump($array[0]); // NULL
var_dump($array[1]); // int(2)

var_dump($array["4"]); // string(3) "foo"

// Increase the size of the array to 10
$array->setSize(10);

$array[9] = "asdf";

// Shrink the array to a size of 2
$array->setSize(2);

// The following lines throw a RuntimeException: Index invalid or out of range
try {
    var_dump($array["non-numeric"]);
} catch(RuntimeException $re) {
    echo "RuntimeException: ".$re->getMessage()."\n";
}

try {
    var_dump($array[-1]);
} catch(RuntimeException $re) {
    echo "RuntimeException: ".$re->getMessage()."\n";
}

try {
    var_dump($array[5]);
} catch(RuntimeException $re) {
    echo "RuntimeException: ".$re->getMessage()."\n";
}
?>

 以上会输出

NULL
int(2)
string(3) "foo"
RuntimeException: Index invalid or out of range
RuntimeException: Index invalid or out of range
RuntimeException: Index invalid or out of range