SplFixedArray::fromArray()

(PHP 5 >= 5.3.0, PHP 7)

Import a PHP array in a SplFixedArray instance

说明

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

Import the PHP array $array in a new SplFixedArrayinstance

参数

$array: The array to import.
$save_indexes: Try to save the numeric indexes used in the original array.

返回值

Returns an instance of SplFixedArray containing the array content.

范例

SplFixedArray::fromArray() example

<?php
$fa = SplFixedArray::fromArray(array(1 => 1, 0 => 2, 3 => 3));
var_dump($fa);
$fa = SplFixedArray::fromArray(array(1 => 1, 0 => 2, 3 => 3), false);
var_dump($fa);
?>

以上例程会输出：

object(SplFixedArray)#1 (4) {
  [0]=>
  int(2)
  [1]=>
  int(1)
  [2]=>
  NULL
  [3]=>
  int(3)
}
object(SplFixedArray)#2 (3) {
  [0]=>
  int(1)
  [1]=>
  int(2)
  [2]=>
  int(3)
}

Memory footprint tests : 
<?php
echo memory_get_usage()."\n"; // display 627760
$array = array_fill( 0, 2048, 'a' );
echo memory_get_usage()."\n"; // 824744, so 196984 for $array
unset( $array );
echo memory_get_usage()."\n"; // 627792
$spl=SplFixedArray::fromArray( array_fill( 0, 2048, 'a' ) );
echo memory_get_usage()."\n"; //644944, so just 17151 for $spl !!!
?>