How to list the keys of an array when the keys are also arrays?

Question

I have a complex array, with structure like the following..

array(3) {
  ["status"]=>
  int(1)
  ["data"]=>
  array(113) {
    [0]=>
    array(3) {
      ["id"]=>
      string(6) "838424"
      ["language"]=>
      NULL
      ["work_start_date"]=>
      string(19) "2003-04-28 00:00:00"
    }
    [1]=>
    array(3) {
      ["id"]=>
      string(6) "839062"
      ["language"]=>
      NULL
      ["work_start_date"]=>
      string(19) "2014-01-15 12:53:00"
    }
  }
}

I can get the "id" of a certain element by using something like the following..

print $my_array["data"]["0"]["id"] . "\n";

But what I want to do is loop through the 0,1 etc elements, and I don't know how to do that. I thought something like the following would do it, but it doesn't work.

foreach ($my_array["data"] as $key) {
   print $my_array["data"][$key]["id"] . "\n";
}

Any insight would be appreciated

I assure you, your array keys are not arrays.

Sam Dufel
– Sam Dufel

2014-01-17 21:48:19 +00:00
Commented Jan 17, 2014 at 21:48 — Sam Dufel
– Sam Dufel, Commented Jan 17, 2014 at 21:48

Mike Brant · Accepted Answer · 2014-01-17 23:14:47Z

You are a little off on your foreach syntax.

You should either do:

foreach($my_array['data'] as $item) {
    print $item['id'] . "\n";
}

Or

foreach($my_array['data'] as $key => $item) {
    print "The item at index position '" . $key . "' has an id of '" . $item['id'] . "'\n";
}

In the first case where foreach syntax with single variable name is used, you actually have no information on the key itself, you only get the values at each index location. This sort of syntax is usually only useful for numerically indexed arrays (which you have in this case).

In the second syntax, you get a variable for both the key and the value that you can reference. This is usually most useful for iterating associative arrays, or for iterating numerical arrays where you need to reference the index position.

In either case, the value present in $item would hold only the value for that array element, you would not need reference back to the containing $my_array variable to access this data.

John · Accepted Answer · 2014-01-17 20:12:17Z

0

Try something like:

foreach (array_keys($my_array["data"]) as $key) {
  print ...
}

answered Jan 17, 2014 at 20:12

John

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1 Comment

Mike Brant Over a year ago

This might not add much value to the OP's understanding of their original error... that being a simple misunderstanding of the foreach() syntax.

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