Is there a php function that someone can use to automatically detect if an array is an associative or not, apart from explictly checking the array keys?
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2I sense something wrong in your design. Why would you want to do this?Randell– Randell2009-07-26 05:13:21 +00:00Commented Jul 26, 2009 at 5:13
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It's not an uncommon need, especially when writing more generic, non application-specific code.grantwparks– grantwparks2012-04-02 06:36:55 +00:00Commented Apr 2, 2012 at 6:36
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possible duplicate of PHP Arrays: A good way to check if an array is associative or sequential?Gordon– Gordon2012-06-19 17:57:23 +00:00Commented Jun 19, 2012 at 17:57
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5 Answers
My short answer: YES
Quicker and easier, IF you make the assumption that a "non-associative array" is indexed starting at 0:
if ($original_array == array_values($original_array))
3 Comments
grantwparks
I feel I have to continue because other answers that take longer are being voted up. One does not have to examine the keys. array_values() returns an integer-indexed array, thus if one compares the array in question with its array_values() and they are equal, the original array is a 0 based, integer indexed array. It is the shortest, slickest way. Try it out.
deceze
I agree, arrays that are not indexed continuously starting at
0 should be considered associative, since they can't be traversed reliably with the typical for ($x++) pattern. Hence this test is probably the best to use. It becomes sort of a philosophical debate though, as PHP arrays simply aren't one or the other. :)grantwparks
I was just trying to pass on the quickest/slickest way I found to determine if the indices are 0 thru N without any kind of explicit inspection of the keys.<p>I love PHP arrays.
quoted from the official site:
The indexed and associative array types are the same type in PHP,
So the best solution I can think of is running on all the keys, or using array_keys,implode,is_numeric
answered May 24, 2009 at 1:36
Itay Moav -Malimovka
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grantwparks
Please see my comment below about comparing the original array to its array_values().
Check out the discussions at is_array.
answered May 24, 2009 at 1:32
Alan Haggai Alavi
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Short answer: no.
Long answer: Associative and indexed arrays are the same type in PHP. Indexed arrays are a subset of associative arrays where:
- The keys are only integers;
- They range from 0 to N-1 where N is the size of the array.
You can try and detect that if you want by using array_keys(), a sort and comparison with a range() result.
