PHP SPL standard library SplFixedArray usage example, splsplfixedarray

PHP SPL standard library SplFixedArray usage example, splsplfixedarray_PHP tutorial

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Release： 2016-07-13 09:54:08

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PHP SPL standard library SplFixedArray usage example, splsplfixedarray

SplFixedArray is mainly the main function related to processing arrays. Different from ordinary php array, it is of fixed length, and The advantage of arrays with numbers as keys is that they are faster to process than ordinary arrays.

Look at my native Benchmark test:

ini_set('memory_limit','12800M');
 
for($size = 10000; $size < 10000000; $size *= 4) {
  echo PHP_EOL . "Testing size: $size" . PHP_EOL;
  for($s = microtime(true), $container = Array(), $i = 0; $i < $size; $i++) $container[$i] = NULL;
  echo "Array(): " . (microtime(true) - $s) . PHP_EOL;
 
  for($s = microtime(true), $container = new SplFixedArray($size), $i = 0; $i < $size; $i++) $container[$i] = NULL;
  echo "SplArray(): " . (microtime(true) - $s) . PHP_EOL;
}

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The results are as follows:

Testing size: 10000
Array(): 0.004000186920166
SplArray(): 0.0019998550415039
 
Testing size: 40000
Array(): 0.017001152038574
SplArray(): 0.0090007781982422
 
Testing size: 160000
Array(): 0.050002098083496
SplArray(): 0.046003103256226
 
Testing size: 640000
Array(): 0.19701099395752
SplArray(): 0.16700983047485
 
Testing size: 2560000
Array(): 0.75704312324524
SplArray(): 0.67303895950317

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Usually SplFixedArray is 20%~30% faster than PHP array, so if you are dealing with a huge number of fixed-length arrays, it is still strongly recommended.
The SplFixedArray class summary is as follows:

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 )
}

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Use SplFixedArray:

$arr = new SplFixedArray(4);
$arr[0] = 'php';
$arr[1] = 1;
$arr[3] = 'python';
 
//遍历， $arr[2] 为null
foreach($arr as $v) {
  echo $v . PHP_EOL;
}
 
//获取数组长度
echo $arr->getSize(); //4
 
//增加数组长度
$arr->setSize(5);
$arr[4] = 'new one';
 
//捕获异常
try{
  echo $arr[10];
} catch (RuntimeException $e) {
  echo $e->getMessage();
}

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