Php 基于另一个数组保留二维数组每行中的元素
我有这个阵列:Php 基于另一个数组保留二维数组每行中的元素,php,arrays,filtering,php-5.6,Php,Arrays,Filtering,Php 5.6,我有这个阵列: 0 => array:3 [ "product_id" => "1138" "product_image" => "/resources/medias/shop/products/shop-6500720--1.png" "product_sku" => "6500722" ] 1 => array:3
0 => array:3 [
"product_id" => "1138"
"product_image" => "/resources/medias/shop/products/shop-6500720--1.png"
"product_sku" => "6500722"
]
1 => array:3 [
"product_id" => "1144"
"product_image" => "/resources/medias/shop/products/shop-6501041--1.png"
"product_sku" => "6501046"
]
2 => array:3 [
"product_id" => "113"
"product_image" => "/resources/medias/shop/products/shop-6294909--1.png"
"product_sku" => "6294915"
]
我要寻找的是一种方法,可以获得只包含必需列的多个数组(array\u column
不是一个选项,因为它只给我一列)
我所做的
function colsFromArray($array, $keys)
{
return array_map(function ($el) use ($keys) {
return array_map(function ($c) use ($el) {
return $el[$c];
}, $keys);
}, $array);
}
$array = array(
[
"product_id" => "1138",
"product_image" => "/resources/medias/shop/products/shop-6500720--1.png",
"product_sku" => "6500722"
],
[
"product_id" => "1144",
"product_image" => "/resources/medias/shop/products/shop-6501041--1.png",
"product_sku" => "6501046"
],
[
"product_id" => "113",
"product_image" => "/resources/medias/shop/products/shop-6294909--1.png",
"product_sku" => "6294915"
]
);
colsFromArray($array, array("product_id", "product_sku"));
//0 => array:3 [
// "product_id" => "1138"
// "product_sku" => "6500722"
// ]
//1 => array:3 [
// "product_id" => "1144"
// "product_sku" => "6501046"
// ]
//2 => array:3 [
// "product_id" => "113"
// "product_sku" => "6294915"
//]
问题是它似乎太滞后了,因为它在这个问题上迭代了两次。
没有这个解决方法,有没有办法获得多个列
我使用的是PHP5.6,如果我正确理解了你的问题,你可以试试传统的foreach,它可能会快一点
function colsFromArray($array, $filterKeys) {
$newArr = [];
foreach($array as $val) {
$element = [];
foreach($filterKeys as $filterKey) {
$element[$filterKey] = $val[$filterKey];
}
$newArr[] = $element;
}
}
(未测试)
问题是它似乎太滞后了,因为它在这个问题上迭代了两次
您的原始代码没有在同一数组上迭代两次。如果希望有一个数组,其中每个元素都是另一个元素数组,其中的键来自filterKeys数组,则无法绕过主数组和filterKeys数组进行迭代。如果需要一个数组中的两列,其中一列是SKU(通常是唯一的)然后可以将array_column与第三个参数一起使用
$new = array_column($arr, "product_id", "product_sku");
这将返回一个平面数组,SKU作为键,ID作为值,使数组也易于使用
输出:
array(3) {
[6500722]=>
string(4) "1138"
[6501046]=>
string(4) "1144"
[6294915]=>
string(3) "113"
}
我认为更大的问题是你丢了钥匙 您可以使用简单的foreach来代替第二个数组映射:
function colsFromArray(array $array, $keys)
{
if (!is_array($keys)) $keys = [$keys];
return array_map(function ($el) use ($keys) {
$o = [];
foreach($keys as $key){
// if(isset($el[$key]))$o[$key] = $el[$key]; //you can do it this way if you don't want to set a default for missing keys.
$o[$key] = isset($el[$key])?$el[$key]:false;
}
return $o;
}, $array);
}
输出
array (
0 =>
array (
'product_id' => '1138',
'product_sku' => '6500722',
),
1 =>
array (
'product_id' => '1144',
'product_sku' => '6501046',
),
2 =>
array (
'product_id' => '113',
'product_sku' => '6294915',
),
)
问题是它似乎太滞后了,因为它在这个问题上迭代了两次
没有真正的方法不迭代它2次,但是您可能也不想扔掉这些键
也就是说,您可以递归地取消设置不需要的项
function colsFromArray(array &$array, $keys)
{
if (!is_array($keys)) $keys = [$keys];
foreach ($array as $key => &$value) {
if (is_array($value)) {
colsFromArray($value, $keys); //recursive
}else if(!in_array($key, $keys)){
unset($array[$key]);
}
}
}
colsFromArray($array, array("product_id", "product_sku"));
var_export($array);
输出与以前相同
通过引用,这更容易做到。不管是不是更快,您必须测试2并查看
最后要注意的是,除非您将键强制转换为数组,否则不应假定该键将存在或键将是数组
您还可以使用数组过滤器来完成此操作
function colsFromArray(array $array, $keys)
{
if (!is_array($keys)) $keys = [$keys];
$filter = function($k) use ($keys){
return in_array($k,$keys);
};
return array_map(function ($el) use ($keys,$filter) {
return array_filter($el, $filter, ARRAY_FILTER_USE_KEY );
}, $array);
}
声明用于在循环之外进行过滤的函数(array_map)有一些小的性能好处
如果您不想更改原始阵列并希望获得所需的输出 使用函数获得所需的输出,如下所示
$array = array(
[
"product_id" => "1138",
"product_image" => "/resources/medias/shop/products/shop-6500720--1.png",
"product_sku" => "6500722"
],
[
"product_id" => "1144",
"product_image" => "/resources/medias/shop/products/shop-6501041--1.png",
"product_sku" => "6501046"
],
[
"product_id" => "113",
"product_image" => "/resources/medias/shop/products/shop-6294909--1.png",
"product_sku" => "6294915"
]
);
$keys = array("product_id"=>1, "product_sku"=>2);
$filteredArray = array_map(function($a) use($keys){
return array_intersect_key($a,$keys);
}, $array);
print_r($filteredArray);
我将@Chayan的优雅方法重构为一个函数,这样就可以像
array\u column()
那样使用它。要过滤的键现在可以显示为一个简单的数组
顺便说一句,这很可能也是最快的方法,因为它使用内置函数来完成大部分繁重的工作
function array_columns(array $arr, array $keysSelect)
{
$keys = array_flip($keysSelect);
return array_map(
function($a) use($keys) {
return array_intersect_key($a,$keys);
},
$arr
);
}
$arr = [
[
"product_id" => "1138",
"product_image" => "/resources/medias/shop/products/shop-6500720--1.png",
"product_sku" => "6500722"
],
[
"product_id" => "1144",
"product_image" => "/resources/medias/shop/products/shop-6501041--1.png",
"product_sku" => "6501046"
],
[
"product_id" => "113",
"product_image" => "/resources/medias/shop/products/shop-6294909--1.png",
"product_sku" => "6294915"
]
];
$keysSelect = ["product_id" , "product_sku"];
$filteredArray = array_columns($arr, $keysSelect);
var_dump($filteredArray);
这是一个基于Chayan的重构函数,添加了选定列的重命名:
array_columns函数的一个新增功能最终可以追溯到Chayan的答案,这次是从Joseph Mangion的函数扩展而来的 我偶尔会有一长串选定的列,在这些列中我希望保留键,而不一定要遵循大量字段的繁琐的
['orignal\u field\u name']=>['original\u field\u name']
格式
默认情况下,此版本会保留每个字段的原始密钥,除非指定了新密钥
// See answer from Joseph Mangion: https://stackoverflow.com/questions/52706383/php-get-multiple-columns-from-array
/** Function - array_columns Selects columns from multidimensional array and renames columns as required
*
* @param array $in_array, array $select_columns_rename_keys
* example of $select_columns_rename_keys:
* ['new_column_name1' => 'original_column_name1', 'original_column_name2', 'original_column_name3', 'new_column_name4' => 'original_column_name4', ...]
* This will use the original keys for columns 2 and 3 and rename columns 1 and 4
* @return array
* @access public
*
*/
public function array_columns($in_array, $select_columns_rename_keys) {
foreach ($select_columns_rename_keys as $k => $v)
if (is_int($k)) {
$select_columns_rename_keys[$v] = $v;
unset($select_columns_rename_keys[$k]);
}
$keys = array_flip($select_columns_rename_keys);
$filtered_array =
array_map(function($a) use($keys) {
$data = array_intersect_key($a, $keys);
$return_array = [];
foreach ($data as $column_name => $value) $return_array[$keys[$column_name]] = $value;
return $return_array;
}, $in_array);
return $filtered_array;
}
嗨@fiskolin,问题不是clear@fiskolin你能解释一下数组是从哪里来的吗?是否可以修改数据的初始提取?更大的问题是您丢失了密钥,这是一个非常干净的解决方案,您还可以使用
array\u flip()
将数组值作为密钥进行筛选!这是另一个问题的正确答案。它不能提供问题中规定的预期结果。(这并不是说这是一项糟糕的技术;它只是偏离了要求。)
/** Function - array_columns Selects columns from multidimantional array and renames columns as required
*
* @param array $arr, array $selectColRenameKeys
* example: (NewName1->colNameneeded1,NewName2->colNameneeded2,ect...)
* @return array
* @access public
*
*/
private function array_columns( $arr,$selectColRenameKeys) {
$keys = array_flip($selectColRenameKeys);
$filteredArray = array_map(function($a) use($keys){
$data = array_intersect_key($a,$keys);
$rename_arr= array();
foreach ($data as $colname => $value){
$r_arr[$keys[$colname]]= $value ;
}
return $r_arr;
}, $arr);
return $filteredArray;
}
// See answer from Joseph Mangion: https://stackoverflow.com/questions/52706383/php-get-multiple-columns-from-array
/** Function - array_columns Selects columns from multidimensional array and renames columns as required
*
* @param array $in_array, array $select_columns_rename_keys
* example of $select_columns_rename_keys:
* ['new_column_name1' => 'original_column_name1', 'original_column_name2', 'original_column_name3', 'new_column_name4' => 'original_column_name4', ...]
* This will use the original keys for columns 2 and 3 and rename columns 1 and 4
* @return array
* @access public
*
*/
public function array_columns($in_array, $select_columns_rename_keys) {
foreach ($select_columns_rename_keys as $k => $v)
if (is_int($k)) {
$select_columns_rename_keys[$v] = $v;
unset($select_columns_rename_keys[$k]);
}
$keys = array_flip($select_columns_rename_keys);
$filtered_array =
array_map(function($a) use($keys) {
$data = array_intersect_key($a, $keys);
$return_array = [];
foreach ($data as $column_name => $value) $return_array[$keys[$column_name]] = $value;
return $return_array;
}, $in_array);
return $filtered_array;
}