给定一个关联数组数组，任务是将它们组合起来，合并数组键并填充缺少的列使用默认值。
<code class="php">$a = array('a' => 'some value', 'b' => 'some value', 'c' => 'some value');
$b = array('a' => 'another value', 'd' => 'another value', 'e' => 'another value', 'f' => 'another value');
$c = array('b' => 'some more value', 'x' => 'some more value', 'y' => 'some more value', 'z' => 'some more value');
$d = array($a, $b, $c);</code>var_export($d)
将输出：
array (
0 =>
array (
'a' => 'some value',
'b' => 'some value',
'c' => 'some value',
),
1 =>
array (
'a' => 'another value',
'd' => 'another value',
'e' => 'another value',
'f' => 'another value',
),
2 =>
array (
'b' => 'some more value',
'x' => 'some more value',
'y' => 'some more value',
'z' => 'some more value',
),
)所需的输出是：
Array
(
[0] => Array
(
[a] => some value
[b] => some value
[c] => some value
[d] =>
[e] =>
[f] =>
[x] =>
[y] =>
[z] =>
)
[1] => Array
(
[a] => another value
[b] =>
[c] =>
[d] => another value
[e] => another value
[f] => another value
[x] =>
[y] =>
[z] =>
)
[2] => Array
(
[a] =>
[b] => some more value
[c] =>
[d] =>
[e] =>
[f] =>
[x] => some more value
[y] => some more value
[z] => some more value
)
)要实现此目的， array_merge()可以使用。
<code class="php">$keys = array();
foreach(new RecursiveIteratorIterator(new RecursiveArrayIterator($d)) as $key => $val) $keys[$key] = '';
$data = array();
foreach($d as $values) {
$data[] = array_merge($keys, $values);
}
echo '<pre class="brush:php;toolbar:false">';
print_r($data);</code>另一种方法是创建密钥对值，然后映射每个 $d 并合并。
<code class="php">$keys = array_keys(call_user_func_array('array_merge', $d));
$key_pair = array_combine($keys, array_fill(0, count($keys), null));
$values = array_map(function($e) use ($key_pair) {
return array_merge($key_pair, $e);
}, $d);</code>以上是如何合并缺少列的关联数组并提供默认值？的详细内容。更多信息请关注PHP中文网其他相关文章！
