在php中将数组值合并为单个键和多个值

问题描述:

I want the array to merge into a key value pair. look at the example below

Here is my code and array $aExtraFilter

array (size=4)
  0 => 
    array (size=2)
      'key' => string 'CookTech' (length=8)
      'value' => string 'Broil' (length=5)
  1 => 
    array (size=2)
      'key' => string 'CookTech' (length=8)
      'value' => string 'Pan Fry' (length=7)
  2 => 
    array (size=2)
      'key' => string 'CookSkills' (length=10)
      'value' => string 'Intro' (length=5)
  3 => 
    array (size=2)
      'key' => string 'CookSkills' (length=10)
      'value' => string 'Knife Skills' (length=12)

Here is my code:

    $aExtraFilter2 = [];
    $extrafilterkey = '';
    $extrafiltervalue = [];
    foreach ($aExtraFilter as $key => $value) {
        $extrafilterkey = $value['key'];
        $aExtraFilter2[$extrafilterkey] = [];
        array_push($extrafiltervalue, $value['value']);
        $aExtraFilter2[$extrafilterkey] = implode(',', $extrafiltervalue);
    }
    var_dump($aExtraFilter2);

the output is :

array (size=2)
  'CookTech' => string 'Broil,Pan Fry' (length=13)
  'CookSkills' => string 'Broil,Pan Fry,Intro,Knife Skills' (length=32)

I want it to look like this:

array (size=2)
  'CookTech' => string 'Broil,Pan Fry' (length=13)
  'CookSkills' => string 'Intro,Knife Skills' (length=32)

I think I'm almost there but I guess I need some help.

This line does nothing because it is superseded just a bit later as the same variable is being set:

$aExtraFilter2[$extrafilterkey] = [];

This line appends to the array regardless of what you have as $value['key'], which is why you get all keys lumped together in the output:

array_push($extrafiltervalue, $value['value']);

This will produce a desired output:

// fill array of arrays
$aExtraFilter2 = [];
foreach ($aExtraFilter as $key => $value) {
    if (!array_key_exists($value['key'], $aExtraFilter2)) $aExtraFilter2[$value['key']] = [];
    $aExtraFilter2[$value['key']][] = $value['value'];
}
// convert to string (if needed at all, depends on what you're doing later)
foreach ($aExtraFilter2 as $key => $set) {
    $aExtraFilter2[$key] = join(',', $set);
}

The typical way to code this is by creating a temporary structure, based on the key and comprising an array with the values:

$tmp = [];
foreach ($aExtraFilter as $pair) {
    $tmp[$pair['key']][] = $pair['value'];
}

The structure would look like this afterwards:

[
    'CookTech' => ['Broil', 'Pan Fry'],
    'CookSkills' => ['Intro', 'Knife Skills'],
]

Then, you map that array against the representation you want to have:

$aExtraFilter2 = array_map(function($values) {
    return join(',', $values);
}, $tmp);

See also: array_map()