Comments on: Five Cool PHP Array Functions

By: Darren

Darren — Tue, 17 Nov 2009 04:54:43 +0000

@Will K, what would be the difference between first() and reset()? I don’t think there would be any. first() would need to move the internal pointer to the beginning of the array and return that element, exactly as reset() does, which is the opposite of end() which moves the internal pointer to the end of the array and returns that element.

By: Richard Lynch

Richard Lynch — Wed, 28 Oct 2009 04:55:28 +0000

array_key_exists works just fine, but it will still return TRUE even if you set the value to NULL for a given index:

$foo[42] = null;
var_dump(array_key_exists($foo, 42)); //TRUE

This can be confusing if you expect NULL to “wipe out” the key/value entirely.

To really get rid of it, use unset:
unset($foo[42]);

Personally, I rarely use NULL in PHP (partially because it didn’t exist for so long) and simply use isset/unset.

I use NULL only when I need to clearly define a NULL value to be sent to a database layer at some point down the line.

By: Brandon Savage

Brandon Savage — Fri, 23 Oct 2009 18:23:39 +0000

I tested it this morning; seems to work just fine. I think you’re doing it wrong.

By: Mohamed Almasry

Mohamed Almasry — Fri, 23 Oct 2009 11:41:57 +0000

array_key_exists this function doesn’t operate properly, I use it tens of times .

By: Will K

Will K — Fri, 23 Oct 2009 11:34:17 +0000

@optik – functions such as end(), next(), prev() change the internal array pointer.

So current() will get the first element until any of the above functions are called, a reset() would then be required. Ideally there should be a first() function!

By: optik

optik — Thu, 22 Oct 2009 08:00:38 +0000

@Oscar – end() for last element and for first? reset() – some php functions are very badly designed

By: Eric B

Eric B — Thu, 22 Oct 2009 05:11:50 +0000

Another interesting thing about array_merge() is that it re-indexes the arrays. You can pass it just one array to have the indexes reset.

$test = array(‘first’, ’second’, ‘third’);
unset($test[1]);
$test = array_merge($test);

‘first’ is now $test[0], ‘third’ is now $test[1].

By: Steve High

Steve High — Thu, 22 Oct 2009 03:47:08 +0000

My favorite is array_map in conjunction with create_function

…
$arrayOfIntegers = array_map(create_function(‘$x’, ‘return intval($x);’), $arrayOfIntegerStrings);

…
As far as array manipulation is concerned, PHP is the bee’s knees ;)

By: Oscar

Oscar — Wed, 21 Oct 2009 18:56:40 +0000

I’d also add that array_reverse and array_diff can be quite handy too.

By: Oscar

Oscar — Wed, 21 Oct 2009 18:55:48 +0000

@robin – thanks, I didn’t know to use end() that way. I knew about those others too so my first though was to abuse them.

By: Robin

Robin — Wed, 21 Oct 2009 18:37:12 +0000

Hm. My example was stripped out :(

$fruits = array(‘apple’, ‘banana’, ‘cranberry’);
echo end($fruits); // cranberry

(copy-paste from http://ua2.php.net/end)

By: Robin

Robin — Wed, 21 Oct 2009 18:34:42 +0000

@omerida You probably know this already, but you can also grab the last element from an array without popping it using the end() function. However, it does change the internal pointer in the array (but doesn’t remove the item).

By: Matthew Turland

Matthew Turland — Wed, 21 Oct 2009 17:02:28 +0000

Don’t forget implode/explode for converting strings to arrays and vice versa. I’ve always said that those two are the duct tape and WD40 of PHP. :)

By: Oscar

Oscar — Wed, 21 Oct 2009 14:55:01 +0000

Great Article – Here are my favorites:
array_filter – by default removes empty elements, but you can pass it a callback to filter
array_chunk – partitions an array
uasort – sorts an array and keeps they keys intact.

And also, to get the last value from an array without modifying it, i use this trick

$last = array_pop(array_values($my_array));

By: Brandon Savage

Brandon Savage — Wed, 21 Oct 2009 14:38:55 +0000

I wanted to present some basic array functions that I often see duplicated in custom PHP code. That’s why I picked the five I did. Thanks for your comment!