如何在PHP中打印带有键和值的数组元素？

$array = array('key1' => 'value1', 'key2' => 'value2', 'key3' => 'value3');
print_r($array);

Array
(
    [key1] => value1
    [key2] => value2
    [key3] => value3
)

$array = array('key1' => 'value1', 'key2' => 'value2', 'key3' => 'value3');
var_dump($array);

array(3) {
  ["key1"]=>
  string(6) "value1"
  ["key2"]=>
  string(6) "value2"
  ["key3"]=>
  string(6) "value3"
}