从嵌套的关联数组中获取单个值

Question

For a setup script I write in PHP (for CLI, not web) I use a settings file as well as other other "content" files.

The settings file is built up like a regular ini-file

[header.subheader.moreheaders...]
keyA = value
keyB = value1|value2|...

"header.subheader.moreheaders..." and "keyX" will form a nested associative array with "value" as a string or "value1|value2|..." as a simple array (0-...).

Thanks to this accepted answer, I got so far that I can split the headers into a recursive array recursively. So far, so good.

However, as the content files shall contain references to these variables, I would like to be able to read out single values from that multi-dimensional array with string placeholders like $@R[header.subheader.moreheaders.key] or $@R[header.subheader.moreheaders.key.0] depending on them being a string or an array.

In the script, $@R[header.subheader.moreheaders.key.0] should convert into $SettingsVar[header][subheader][moreheaders][key][0] to return the appropriate value.

Neither the script nor the content files will know what is inside the settings file. The script just knows the general structure and placeholder $@R[...].

This answer appears to know what value will be in order to search for it.

Since I do not fully understand this answer, I am not sure if that would be the right way.

Is there a similar easy way to get the reverse from building that array?

Answer 1

After some contemplation, I found a decent enough solution, which works for me (and hopefully others):

function GetNestedValue($aNestedKeys, $aNestedArray)
{
    $vValue = $aNestedArray;
    for($i = 0; $i < count($aNestedKeys); $i++)
    {
        if(array_key_exists($aNestedKeys[$i], $vValue))
        {
            $vValue = $vValue[$aNestedKeys[$i]];
        }
        else
        {
            $vValue = null;
            break;
        }
    }

    return $vValue;
}

Depending on what $aNestedKeys contain, it will either return a sub-array from $aNestedArray, a single value from it or null if any of the specified keys were not found.