Question

Below is a sample of the structure of the array. I need to be able to pull out specific values such as : [245][subfields][a]. There are a variable number of [fields] and a variable number of [subfields] inside each of the array. Thanks for any suggestions!

Edit: I have included the array in its navtive JSON format that I am retrieving. I was then using json_decode to convert this into a usable array in php. If you have a better suggestion, please let me know.

Link to pretty array

{"leader":"01220nam  2200265   4500","fields":[{"001":"ocm00000197"},{"005":"19880526181046.0"},{"008":"690325r19681924nyua          00000 eng  "},{"010":{"ind1":" ","ind2":" ","subfields":[{"a":"67-020193 \/\/r832"}]}},{"035":{"ind1":" ","ind2":" ","subfields":[{"a":".b10000021"},{"b":"a    "},{"c":"-"}]}},{"041":{"ind1":"1","ind2":" ","subfields":[{"a":"eng"},{"a":"fre"}]}},{"049":{"ind1":" ","ind2":" ","subfields":[{"a":"JBLA"},{"c":"$8.00"}]}},{"100":{"ind1":"1","ind2":"0","subfields":[{"a":"Allemagne, Henry Ren\u00e2e d',"},{"d":"1863-1950."}]}},{"245":{"ind1":"1","ind2":"0","subfields":[{"a":"Decorative antique ironwork :"},{"b":"a pictorial treasury \/"},{"c":"by Henry Ren\u00e2e d'Allemagne ; introd., bibliography, and translation of captions by Vera K. Ostoia."}]}},{"260":{"ind1":"0","ind2":" ","subfields":[{"a":"New York :"},{"b":"Dover Publications,"},{"c":"[1968]"}]}},{"300":{"ind1":" ","ind2":" ","subfields":[{"a":"x, 415 p. :"},{"b":"(chiefly ill.) ;"},{"c":"31 cm."}]}},{"500":{"ind1":" ","ind2":" ","subfields":[{"a":"\"This Dover edition ... is a republication of all the plates in the two portfolios of Mus\u00e2ee Le Secq des Tournelles \u00e1a Rouen: Ferronnerie ancienne, originally published ... in 1924.\""}]}},{"500":{"ind1":" ","ind2":" ","subfields":[{"a":"\"Other books by Henry Ren\u00e2e d'Allemagne\": p. x."}]}},{"590":{"ind1":" ","ind2":" ","subfields":[{"a":"1373336."}]}},{"650":{"ind1":" ","ind2":"0","subfields":[{"a":"Art metal-work."}]}},{"700":{"ind1":"1","ind2":"0","subfields":[{"a":"Ostoia, Vera K."}]}},{"710":{"ind1":"2","ind2":"0","subfields":[{"a":"Mus\u00e2ee Le Secq des Tournelles."}]}},{"830":{"ind1":" ","ind2":"0","subfields":[{"a":"Dover pictorial archive series."}]}},{"999":{"ind1":" ","ind2":" ","subfields":[{"b":"1"},{"c":"901102"},{"d":"m"},{"e":"b"},{"f":"-"},{"g":"0"}]}},{"945":{"ind1":" ","ind2":" ","subfields":[{"a":"739.4\/ALLEMAGNE,H"},{"g":"1"},{"i":"31184001373336"},{"l":"abx7 "},{"n":"moved from RESEARCH collection - Feb 2012"},{"o":"-"},{"p":"$8.00"},{"s":"-"},{"t":"235"},{"u":"10"},{"v":"0"},{"w":"0"},{"x":"1"},{"y":".i10000021"},{"z":"901102"}]}}]}

Answer 1

So it looks like you’ll need a method to loop over the fields key to check the first key of each of its sub-arrays to match your searched item.

// Loop over the fields, which are each arrays numerically indexed...
foreach ($record['fields'] as $key => $field) {
  // Get the field's first array key, which is 010, 015, etc...
  $marc_keys = array_keys($field);
  // the first key...
  $marc_field = $marc_keys[0];
  // Note in PHP 5.4 you could dereference it more easily like
  // $marc_field = array_keys($field)[0];

  // Test if the key you found is the one you want...
  if ($marc_field == '245') {
     foreach ($field[$marc_field]['subfields'] as $subkey => $subfield) {
       // Get the subfield identifier (the first array key)
       $sf_keys = array_keys($subfield);
       $sf_identifier = $sf_keys[0];
       if ($sf_identifier == 'a') {
          // Congratulations Arthur, you found the grail....
          // Do something with it...
       } 
     }
  }
  // Otherwise, keep looping until you find the one you need...
}

As a function:

You are best served to convert this to a function that accepts the $field,$subfield as parameters:

Updated to account for multiple subfields of the same type, and return an array:

function getSubfield($record, $in_field, $in_subfield) {
    // Array to hold output for multiple like subfields
    $subfields_returned = array();

    foreach ($record['fields'] as $key => $field) {
      $marc_keys = array_keys($field);
      $marc_field = $marc_keys[0];

      // Test if the key you found is the one you want (which is the $in_field param)
      if ($marc_field == $in_field) {
         foreach ($field[$marc_field]['subfields'] as $subkey => $subfield) {

           $sf_keys = array_keys($subfield);
           $sf_identifier = $sf_keys[0];

           // And match the subfield to the function param $in_subfield

           if ($sf_identifier == $in_subfield) {
              // Congratulations Arthur, you found the grail....
              // Return it...
              $subfields_returned[] = $subfield[$sf_identifier];
           }
         }
          // After the subfield loop, you can return the accumulated array
         if (count($subfields_returned) > 0) return $subfields_returned;
      }
      // Otherwise, keep looping until you find the one you need...
    }
}

Here is a demonstration

…With a record I cobbled together partially…