The SplFixedArray class

(PHP 5 >= 5.3.0, PHP 7)

简介

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 count ( void ) : int

public current ( void ) : mixed

public static fromArray ( array $array [, bool $save_indexes = TRUE ] ) : SplFixedArray

public getSize ( void ) : int

public key ( void ) : int

public next ( void ) : void

public offsetExists ( int $index ) : bool

public offsetGet ( int $index ) : mixed

public offsetSet ( int $index , mixed $newval ) : void

public offsetUnset ( int $index ) : void

public rewind ( void ) : void

public setSize ( int $size ) : bool

public toArray ( void ) : array

public valid ( void ) : bool

public __wakeup ( void ) : 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";
}
?>

以上例程会输出：

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

SplFixedArray::__construct — Constructs a new fixed array
SplFixedArray::count — Returns the size of the array
SplFixedArray::current — Return current array entry
SplFixedArray::fromArray — Import a PHP array in a SplFixedArray instance
SplFixedArray::getSize — Gets the size of the array
SplFixedArray::key — Return current array index
SplFixedArray::next — Move to next entry
SplFixedArray::offsetExists — Returns whether the requested index exists
SplFixedArray::offsetGet — Returns the value at the specified index
SplFixedArray::offsetSet — Sets a new value at a specified index
SplFixedArray::offsetUnset — Unsets the value at the specified $index
SplFixedArray::rewind — Rewind iterator back to the start
SplFixedArray::setSize — Change the size of an array
SplFixedArray::toArray — Returns a PHP array from the fixed array
SplFixedArray::valid — Check whether the array contains more elements
SplFixedArray::__wakeup — Reinitialises the array after being unserialised

The SplFixedArray class

简介

类摘要

范例

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