Empty return value from a php array

Question

I have the following...

/* Request access tokens from twitter */
$access_token = $connection->getAccessToken($_REQUEST['oauth_verifier']);

$_SESSION['access_token'] = $access_token;
echo $access_token[2];

"$access_token" is an array, Im trying to retrieve a value from this array only the above echo doesn't seem to echo anything?

dump var

array(4) { ["oauth_token"]=> string(50) "81920494-vHspkpas4WiOYoFKCgto85mW2XeTxuA130MwcHHWb" ["oauth_token_secret"]=> string(42) "WwIYybFivEwZQ1ORbeqY1irHT385EIuh27alWy9ED4" ["user_id"]=> string(8) "81989494" ["screen_name"]=> string(12) "KlareB" }

You really seem to have a problem comprehending arrays. If the key says ["user_id"], then the key is ["user_id"]. Only if the key says [2], then the key is [2]. — deceze
– deceze ♦, Commented May 28, 2013 at 19:50

Phil Cross · Accepted Answer · 2013-05-28 19:49:04Z

5

If the var_dump is:

array(4) { ["oauth_token"]=> string(50) "81920494-vHspkpas4WiOYoFKCgto85mW2XeTxuA130MwcHHWb" ["oauth_token_secret"]=> string(42) "WwIYybFivEwZQ1ORbeqY1irHT385EIuh27alWy9ED4" ["user_id"]=> string(8) "81920494" ["screen_name"]=> string(12) "KlareBrennan" }

Then echo $access_array[2]; wont work because its not indexed numerically.

You would need to do:

echo $access_array['user_id'];

answered May 28, 2013 at 19:49

Phil Cross

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2 Comments

Liam Over a year ago

Thanks, didn't realise was so simple

Phil Cross Over a year ago

No problem :) its not easy unless you know how to do it.

Nathaniel Ford · Accepted Answer · 2013-05-28 20:17:32Z

It is necessary to remember than in PHP arrays are actually hashmaps. That is to say that they are an associative array of key => value pairs.

$_SESSION['access_token'] = $access_token;
echo $access_token[2];

This means the above code will look in the $access_token array not at position 2 but at key 2. We can see from your vardump there is no key 2:

array(4) { 
  ["oauth_token"]=> string(50) "81920494-vHspkpas4WiOYoFKCgto85mW2XeTxuA130MwcHHWb
  ["oauth_token_secret"]=> string(42) "WwIYybFivEwZQ1ORbeqY1irHT385EIuh27alWy9ED4" 
  ["user_id"]=> string(8) "81920494" 
  ["screen_name"]=> string(12) "KlareBrennan" 
}

Note that for most indexed arrays this functions exactly the same way, which is what leads to your confusion. Please consider the following code:

<?php

  $blah = array();
  $blah['mykey'] = "My first key.";
  $blah[] = "My second key.";
  $blah[1] = "My third key.";
  $blah[] = "My last key.";

  var_dump($blah);

And it's results:

array(4) {
  ["mykey"]=>
  string(13) "My first key."
  [0]=>
  string(14) "My second key."
  [1]=>
  string(13) "My third key."
  [2]=>
  string(12) "My last key."
}

We can see that if no key is specified the next available key is use; and in this numerals are assigned as keys for the key-value pair, but that they can live alongside string keys. For this reason array_values() is a useful function if you want to iterate over all the contents of an array.

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