从关联数组中提取值的子集（PHP） [英] Extracting a subset of values from an associative array (php)

问题描述

我想要做一些看似很简单，但我无法找到任何关于它：简单地提取相似的阵列array_splice的一个子集，但是的使用键来检索值的：

I want to do something seemingly very simple, but I can't find anything about it: simply extract a subset of an array similar to array_splice, but using keys to retrieve the values :

$data = array('personName' => 'John', 'personAge' => 99, 'personId' => 1,  
              /* many more data I don't need here ... */);

list($name, $age, $id) = array_splice_by_keys($data,
                          array('personName', 'personAge', 'personId');

如果一切都失败了，是不是有一个内置函数，以滤除键关联数组？例如：

If all else fails, isn't there a builtin function to filter an associative array by keys? For example:

$ filteredArray = array__extract__keys__and__values​​（$ srcArray，$ arrayOfWantedKeys）;

// create a new array with ONLY those key => values I need
$wanted_values = array_extract_keys_and_values($data,
                  array('personName', 'personAge', 'personId');

echo $wanted_values['personName'];

我想，为什么我想要做的第一个原因，就是我不喜欢重复关联数组访问都在我的code，它似乎更好地优化复制时使用了大量的数值（在例如环），在局部变量，再加上它更容易输入$命名超过$的someArray ['名']。

I guess the reason why I want to do the first one, is that I don't like to repeat associative array access all over my code, it would seem better optimized to copy the values that are used a lot (in a loop for example), into a local variable, plus it's much easier to type $name than $somearray['name'].

编辑：谢谢，我想与列表的使用，解决办法是

Thanks, I guess for use with list, the solution would be

list($x, $y, $z) = array_values(array_intersect_key($array, array_flip($wantedKeys)));

Intesresting使用array_flip的！

Intesresting use of array_flip!

推荐答案

在PHP版本> = 5.1.0可以使用的 array_intersect_key ：

in php version >= 5.1.0 you could use array_intersect_key:

$data = array('personName' => 'John', 'personAge' => 99, 'personId' => 1,  
          'test' => 23);
$ex = array('personName'=>0, 'personAge'=>0, 'personId'=>0);
var_dump(array_intersect_key($data, $ex));

在 $前值并不重要，他们只需要为present。

values in $ex don't matter, they just have to be present.

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