Php foreach循环中附加数组方法的比较
我已经设置了一个关联数组(带有虚拟数据用于测试),如下所示:Php foreach循环中附加数组方法的比较,php,arrays,loops,multidimensional-array,foreach,Php,Arrays,Loops,Multidimensional Array,Foreach,我已经设置了一个关联数组(带有虚拟数据用于测试),如下所示: // To hold dropdown filter options $results['filters'] = array('Client' => array( array('a' => '1') ), 'Project' => array( array('b' => '2') ), 'Statu
// To hold dropdown filter options
$results['filters'] = array('Client' => array( array('a' => '1') ),
'Project' => array( array('b' => '2') ),
'Status' => array( array('c' => '3') ),
'User' => array( array('d' => '4') )
);
$newResults = array();
foreach($results['filters'] as $filter_key => $filter_value) {
$newResults[$filter_key] = array('name' => 'All');
}
$results['filters'] = $newResults;
谁能告诉我为什么这样做:
// Add 'All' option to the top of each filter dropdown
foreach($results['filters'] as $filter_key => $filter_value) {
$results['filters'][$filter_key][] = array('name' => 'All');
}
但这并不是:
// Add 'All' option to the top of each filter dropdown
foreach($results['filters'] as $filter_key => $filter_value) {
$filter_value[] = array('name' => 'All');
}
当我在循环内部执行print\r($results)
时,它似乎在工作(将行附加到现有数据),但在循环外部检查它会使循环看起来对数组没有影响
谢谢您需要传递
$filter\u值
作为参考(带前导的&
)而不是副本
foreach($results['filters'] as $filter_key => &$filter_value) {
$filter_value[] = array('name' => 'All');
}
:
以便能够直接修改循环中的数组元素
在$value前面加上&。在这种情况下,该值将由
参考资料
如果我理解正确-在下面的代码中,您只是将值赋给$filter\u值,而不是其父数组:
// Add 'All' option to the top of each filter dropdown
foreach($results['filters'] as $filter_key => $filter_value) {
$filter_value[] = array('name' => 'All');
}
你可以这样做:
// To hold dropdown filter options
$results['filters'] = array('Client' => array( array('a' => '1') ),
'Project' => array( array('b' => '2') ),
'Status' => array( array('c' => '3') ),
'User' => array( array('d' => '4') )
);
$newResults = array();
foreach($results['filters'] as $filter_key => $filter_value) {
$newResults[$filter_key] = array('name' => 'All');
}
$results['filters'] = $newResults;
啊,谢谢你的快速回答,现在这很有道理了。我很惊讶我以前从未遇到过这样的事情。