将一个数组追加到另一个数组(不是array_push或+)

$a = array( 'a', 'b' );
$b = array( 'c', 'd' );

Array( [0]=>a [1]=>b [2]=>Array( [0]=>c [1]=>d ) )
Array( [0]=>c [1]=>d )

foreach ( $b AS $var )
    $a[] = $var;

$appended = $a + $b;

$appended = array_merge($a,$b);

$a = array('a', 'b');
$b = array('c', 'd');
$merge = array_merge($a, $b); 
// $merge is now equals to array('a','b','c','d');

$merge = $a + $b;
// $merge now equals array('a','b')

$array1 = array_fill(0,50000,'aa');
$array2 = array_fill(0,100,'bb');
// Test 1 (array_merge)
$start = microtime(true);
$r1 = array_merge($array1, $array2);
echo sprintf("Test 1: %.06f\n", microtime(true) - $start);
// Test2 (avoid copy)
$start = microtime(true);
foreach ($array2 as $v) {
    $array1[] = $v;
echo sprintf("Test 2: %.06f\n", microtime(true) - $start);
// Test 1: 0.004963
// Test 2: 0.000038

// Test 1 (array_merge)
$array1 = $array2 = array_fill(0, 50000, 'aa');
$start = microtime(true);
$array1 = array_merge($array1, $array2);
echo sprintf("Test 1: %.06f\n", microtime(true) - $start);
// Test2 (foreach)
$array1 = $array2 = array_fill(0, 50000, 'aa');
$start = microtime(true);
foreach ($array2 as $v) {
    $array1[] = $v;
echo sprintf("Test 2: %.06f\n", microtime(true) - $start);
// Test 3 (... token)
// PHP 5.6+ and produces error if $array2 is empty
$array1 = $array2 = array_fill(0, 50000, 'aa');
$start = microtime(true);
array_push($array1, ...$array2);
echo sprintf("Test 3: %.06f\n", microtime(true) - $start);

Test 1: 0.002717 
Test 2: 0.006922 
Test 3: 0.004744

$products = array();
//just example
for($brand_id=1;$brand_id<=3;$brand_id++){
  array_merge($products,getByBrand($brand_id));
// it will create empty array
print_r($a);
//check if array of products is empty
for($brand_id=1;$brand_id<=3;$brand_id++){
  if(empty($products)){
    $products = getByBrand($brand_id);
  }else{
    array_merge($products,getByBrand($brand_id));
// it will create array of products

array_splice($a, count($a), 0, $b);

// Create an array of arrays
$chars = [];
for ($i = 0; $i < 15000; $i++) {
    $chars[] = array_fill(0, 10, 'a');
// test array_merge
$new = [];
$start = microtime(TRUE);
foreach ($chars as $splitArray) {
    $new = array_merge($new, $splitArray);
echo microtime(true) - $start; // => 14.61776 sec
// test foreach
$new = [];
$start = microtime(TRUE);
foreach ($chars as $splitArray) {

将一个数组追加到另一个数组(不是array_push或+)

8 个回答