PHP 用于从多维数组中删除不需要的元素，并参考所需元素列表

Question

编辑：在此处下载示例数据 -> $csv

顶级的产品阵列是$csv. 在下面的摘录中，数字 [584]，[585] 表示下一个数组级别，$product=>$data_col如下所示：

[584] => Array
(
[No_] => II14511
[Manufacturer ID] => CLT-M504S
[Description] => SAM CON CLT-M504S
[LQ Price] => 120.00000000000000000000
[Retail Price Incl_ GST] => 171.60000000000000000000
[AvailableQty] => 0.00000000000000000000
[Rocklea] => 0.00000000000000000000
[Sydney] =>
[Net Weight] => 0.50000000000000000000
[Item Category Code] => SAM
[Product Group Code] => CON
[Minor Category 1] => TONER
[Minor Category 2] => #
[Vendor Name] => Samsung
[Vendor URL] => www.samsung.com.au
[Item URL] =>
[Warranty] =>
[Dimension] =>
[EAN Barcode] => 8806085031999
[Description1] => Samsung CLT-M504S, SEE toner for CLP-415/ CLX-4195 Series LBP & MFP - Magenta Toner 1800 pages<br />
[Image] => https://auscompcomputers.com/uploads/image/SAM-CON-CLT-M504S.jpg
)

[585] => Array
(
[No_] => II14772
[Manufacturer ID] => DK-22205
[Description] => BRO CON LABELROLL-DK-22205
[LQ Price] => 25.00000000000000000000
[Retail Price Incl_ GST] => 35.75000000000000000000
[AvailableQty] => 0.00000000000000000000
[Rocklea] => 0.00000000000000000000
[Sydney] => 0.00000000000000000000
[Net Weight] => 0.50000000000000000000
[Item Category Code] => BRO
[Product Group Code] => CON
[Minor Category 1] => CON-LABEL-ROLL
[Minor Category 2] => #
[Vendor Name] => Brother
[Vendor URL] => www.brother.com
[Item URL] =>
[Warranty] =>
[Dimension] =>
[EAN Barcode] => 4977766628198
[Description1] => Brother DK-22205 ,White Continuous Paper Roll 62mm x 30.48m<br />
[Image] => https://auscompcomputers.com/uploads/image/BRO-CON-LABELROLL-DK-22205.jpg
)

因此，我有一个结构为$csv as $product as $data_col => $value

但是，我想有选择地删除一些$data_col数组，参考我称之为$wanted_data_cols的通缉$data_col列表。

我尝试过的：

//The list of $data_col that I wish to keep
$wanted_data_cols = array('Manufacturer ID','LQ Price','AvailableQty','Net Weight','Item Category Code','Product Group Code','Minor Category 1','Vendor Name','Warranty,Dimension','EAN Barcode','Description1','Image');
//If key is not found in $wanted_data_cols, then delete $data_col
foreach ($csv as $product){
foreach ($product as $data_col){
if(!in_array($data_col,$wanted_data_cols)){
unset($csv[$product][$data_col]);
}
}
}

print_r($csv);

它似乎不会导致整个数组发生变化。 你能建议如何做到这一点吗，或者如果你觉得你有一个更好的解决方案来实现同样的事情，我会接受的。

Answer 1

现有代码的问题在于，当您尝试unset()值时，您正在使用实际值而不是索引来删除该项 - 这将不起作用。

要修复原始代码 -

foreach ($csv as $key => $product){
foreach ($product as $column => $data_col){
if(!in_array($column,$wanted_data_cols)){
unset($csv[$key][$column]);
}
}
}

另一种方法是使用array_intersect_key()，这允许您只保留第二个数组中的键。 要做到这一点 - 你需要在要保留的字段上使用array_flip()，这样字段名称最终会成为键......

$wanted_data_cols = array_flip($wanted_data_cols);
foreach ($csv as $key => $product){
$csv[$key] = array_intersect_key($product, $wanted_data_cols);
}

最后一个建议是，如果可能的话，这应该在加载数据时完成，这样可以节省在内存中保存无用的数据，并且无需执行第二次循环。