Làm cách nào để lặp lại một mảng trong PHP?

// Using short array syntax.
// Also, works with array() syntax.
$arr1 = [1, 2, 3];
$arr2 = [...$arr1]; //[1, 2, 3]
$arr3 = [0, ...$arr1]; //[0, 1, 2, 3]
$arr4 = [...$arr1, ...$arr2, 111]; //[1, 2, 3, 1, 2, 3, 111]
$arr5 = [...$arr1, ...$arr1]; //[1, 2, 3, 1, 2, 3]

function getArr() {
return ['a', 'b'];
}
$arr6 = [...getArr(), 'c' => 'd']; //['a', 'b', 'c' => 'd']
?>

The following function (similar to one above) will render an array as a series of HTML select options (i.e. ""). The problem with the one before is that there was no way to handle, so this function solves that issue.

function arrayToSelect($option, $selected = '', $optgroup = NULL)
{
    $returnStatement = '';

    if ($selected == '') {
        $returnStatement .= '';
    }

    if (isset($optgroup)) {
        foreach ($optgroup as $optgroupKey => $optgroupValue) {
            $returnStatement .= '';

            foreach ($option[$optgroupKey] as $optionKey => $optionValue) {
                if ($optionKey == $selected) {
                    $returnStatement .= '';
                } else {
                    $returnStatement .= '';
                }
            }

            $returnStatement .= '';
        }
    } else {
        foreach ($option as $key => $value) {
            if ($key == $selected) {
                $returnStatement .= '';
            } else {
                $returnStatement .= '';
            }
        }
    }

________số 8_______

So, for example, I needed to render a list of states/provinces for various countries in a select field, and I wanted to use each country name as anlabel. So, with this function, if only a single array is passed to the function (i.e. "arrayToSelect($stateList)") then it will simply spit out a bunch of "

Here's a further example:

$countryList = array(
    'CA'        => 'Canada',
    'US'        => 'United States');

function arrayToSelect($option, $selected = '', $optgroup = NULL)
{
    $returnStatement = '';0

function arrayToSelect($option, $selected = '', $optgroup = NULL)
{
    $returnStatement = '';1

function arrayToSelect($option, $selected = '', $optgroup = NULL)
{
    $returnStatement = '';2

function arrayToSelect($option, $selected = '', $optgroup = NULL)
{
    $returnStatement = '';3

Here's a PHP version of print_r which can be tailored to your needs. Shows protected and private properties of objects and detects recursion (for objects only!). Usage:

void u_print_r ( mixed $expression [, array $ignore] )

Use the $ignore parameter to provide an array of property names that shouldn't be followed recursively.

function u_print_r($subject, $ignore = array(), $depth = 1, $refChain = array())
{
    if ($depth > 20) return;
    if (is_object($subject)) {
        foreach ($refChain as $refVal)
            if ($refVal === $subject) {
                echo "*RECURSION*\n";
                return;
            }
        array_push($refChain, $subject);
        echo get_class($subject) . " Object ( \n";
        $subject = (array) $subject;
        foreach ($subject as $key => $val)
            if (is_array($ignore) && !in_array($key, $ignore, 1)) {
                echo str_repeat(" ", $depth * 4) . '[';
                if ($key{0} == "\0") {
                    $keyParts = explode("\0", $key);
                    echo $keyParts[2] . (($keyParts[1] == '*')  ? ':protected' : ':private');
                } else
                    echo $key;
                echo '] => ';
                u_print_r($val, $ignore, $depth + 1, $refChain);
            }
        echo str_repeat(" ", ($depth - 1) * 4) . ")\n";
        array_pop($refChain);
    } elseif (is_array($subject)) {
        echo "Array ( \n";
        foreach ($subject as $key => $val)
            if (is_array($ignore) && !in_array($key, $ignore, 1)) {
                echo str_repeat(" ", $depth * 4) . '[' . $key . '] => ';
                u_print_r($val, $ignore, $depth + 1, $refChain);
            }
        echo str_repeat(" ", ($depth - 1) * 4) . ")\n";
    } else
        echo $subject . "\n";
}

?>

Example:

class test {

    public $var1 = 'a';
    protected $var2 = 'b';
    private $var3 = 'c';
    protected $array = array('x', 'y', 'z');

}

$test = new test();
$test->recursiveRef = $test;
$test->anotherRecursiveRef->recursiveRef = $test;
$test->dont->follow = 'me';

void u_print_r ( mixed $expression [, array $ignore] )0

?>

void u_print_r ( mixed $expression [, array $ignore] )2

void u_print_r ( mixed $expression [, array $ignore] )3

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