I am reading in a file with thousands of lines. I grab the id from each line and check to see if it is in a multiarray, that also has thousands of entries. If it is in the multiarray I need to have the key of the array it is in. I have this all working with the code shown below but it takes a very long time. I'm hoping someone can suggest a way to do it faster?

    $array = [['id' => 'A202977', '550' => 0, '710' => 0],
              ['id' => 'A202978', '550' => 0, '710' => 0],
              ['id' => 'A202979', '550' => 0, '710' => 0]
             ];

    $found = InMultiArray('A202978', $array);
    $key = MultiArraySearch('A202978', $array);
    echo 'Found '.$found .' at '.$key.'<br>';
    //shows Found 1 at 1

    function InMultiArray($needle, $haystack, $strict = false) {
        foreach ($haystack as $item) {
            if (($strict ? $item === $needle : $item == $needle) || (is_array($item) && InMultiArray($needle, $item, $strict))) {
                return true;
            }
        }
        return false;
    }  
       
    function MultiArraySearch($needle, $haystack) {
        foreach ($haystack as $key => $item) {
            if (($needle == $item['id'])) {
                return $key;
           }        
       }
       return FALSE;
    }

CodePudding user response：

You can safely and soundly cache the resulting resources into a JSON file, so next time when you need to load the data, you can just grab the content of the JSON file and pass it as a parameter to json_decode.

So, this is how you could proceed:

• if the cached file does not exist or it is old, or it is older than the input file
  • proceed in the old and slow way
  • pass the result to json_encode and save it into a cache file
• else
  • load the cache file's content
  • pass it as a parameter to json_decode and you have your result

Alternatively, you can use a database or even a cache-system, like Redis.

CodePudding user response：

If you really need to find the index of the row by the ID field, you can create an associative array of IDs to array indices.

$array = [['id' => 'A202977', '550' => 0, '710' => 0],
          ['id' => 'A202978', '550' => 0, '710' => 0],
          ['id' => 'A202979', '550' => 0, '710' => 0]
];

// Array to map ID to array index in $dataRaw
$idIndexMap = [];

// Populate structs
foreach ($array as $i=>$currRow)
{
    $idIndexMap[$currRow['id']] = $i;
}

$found = array_key_exists('A202978', $idIndexMap);
$key   = $idIndexMap['A202978'];
echo 'Found ' . $found . ' at ' . $key . '<br>';
//shows Found 1 at 1

However if you just need to find the actual row by the ID, it's probably easier to just create an associative array that maps the ID to the actual row.

<?php
$array = [['id' => 'A202977', '550' => 0, '710' => 0],
          ['id' => 'A202978', '550' => 0, '710' => 0],
          ['id' => 'A202979', '550' => 0, '710' => 0]
];

// Array to map ID to array index in $dataRaw
$map = [];

// Populate structs
foreach ($array as $currRow)
{
    $map[$currRow['id']] = $currRow;
}

$found = array_key_exists('A202978', $map);
$row   = $map['A202978'];
echo 'Found ' . json_encode($row) . '<br>';