How to find keys in multidimensional arrays in PHP?

My array is like this:

$arr = array(
'a' => Array(
'1' => '[Large]',
'2' => '[Small]',
'3' => ' [More]',
'4' => '[Less]',
)
'b' => Array(
'1' => '[You]',
'2' => ' [I]',
'3' => '[Her]',
'4' => '[It]',
)
)

I want [you] to be able to find 1 and also find the key b one level up.

array_search seems to only be able to search for one-dimensional arrays, please tell me.

Reply content:

My array is like this:

$arr = array(
'a' => Array(
'1' => '[Large]',
'2' => '[Small]',
'3' => ' [More]',
'4' => '[Less]',
)
'b' => Array(
'1' => '[You]',
'2' => ' [I]',
'3' => '[Her]',
'4' => '[It]',
)
)

I want [you] to be able to find 1 and also find the key b one level up.

array_search seems to only be able to search for one-dimensional arrays, please tell me.

Have you ever done a function similar to Infinitus classification? ? Do you know how the table for this function is designed? ?

For example: product classification table

<code>cat_id  cat_name  pid 
  1       test     0
  2       test1    0
  3       test3    0
  4       test4    1
  5       test5    2
  ......
</code>

This should be familiar to you. If I give you a category ID, what should I do if I want to find all its subcategories including itself? ? Or find all his parent classes including towers? ?

Regarding your question, if you have a way to format the key names of the multi-dimensional array into a structure similar to the table above, then you provide a value, find the key corresponding to the value in the array, and then use the formatted array Search inside and you'll get the results you want.

Traverse each sub-array. When traversing, remember to put the name of the sub-array into the cumulative variable. When you finally find it, output the cumulative variable.

In fact, it is to search for leaf nodes in the tree

I don’t know if this is what you want.

<code>foreach ($arr as $key=>$value) {
    $ikey = array_search('[你]', $value);
    if ($ikey) {
       echo $key,'--',$ikey,'<br>';
    }
}</code>