Turn array into independent function arguments - howto?

Question

I want to use values in an array as independent arguments in a function call. Example:

// Values "a" and "b"
$arr = array("alpha", "beta");
// ... are to be inserted as $a and $b.
my_func($a, $b)
function my_func($a,$b=NULL) { echo "{$a} - {$b}"; }

The number of values in the array are unknown.

Possible solutions:

I can pass the array as a single argument - but would prefer to pass as multiple, independent function arguments.
implode() the array into a comma-separated string. (Fails because it's just one string.)

Using a single parameter:

$str = "'a','b'";
function goat($str);  // $str needs to be parsed as two independent values/variables.

Use eval()?
Traverse the array?

Suggestions are appreciated. Thanks.

"The number of values in the array are unknown." -- are they at least known to match the function signature's arg list? — grantwparks
– grantwparks, Commented Sep 23, 2009 at 17:26

Jay Paroline · Accepted Answer · 2016-02-10 03:23:52Z

36

This question is fairly old but there is finally more direct support for this in PHP 5.6+:

http://php.net/manual/en/functions.arguments.php#functions.variable-arg-list.new

$arr = array("alpha", "beta");
my_func(...$arr);

answered Feb 10, 2016 at 3:23

Jay Paroline

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Comments

karim79 · Accepted Answer · 2009-09-23 17:08:55Z

27

if I understand you correctly:

$arr = array("alpha", "beta");
call_user_func_array('my_func', $arr);

edited Sep 23, 2009 at 17:08

karim79

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answered Sep 23, 2009 at 17:07

Valentin Golev

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Comments

Lance Rushing · Accepted Answer · 2009-09-23 17:04:46Z

0

try list()

// Values "a" and "b"
$arr = array("alpha", "beta");
list($a, $b) = $arr;
my_func($a, $b);

function my_func($a,$b=NULL) { echo "{$a} - {$b}"; }

answered Sep 23, 2009 at 17:04

Lance Rushing

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4 Comments

cwallenpoole Over a year ago

Not technically correct (call_user_func_array is how you are supposed to do this type of behavior, but this is very clever. +1

Kristoffer Bohmann Over a year ago

Good suggestion. You can then use a standard function call (without call_user_func_array) which keeps the code clean. The only pitfall is that list requires you to hard-code the arguments ... list($a, $b) ... while I don't the number of array values in advance.

Matt Fletcher Over a year ago

I was thinking about list() when I was looking this question up, but it doesn't allow for an infinite amount of parameters, does it?

TimSparrow Over a year ago

The number of elements in the array is unknown, so it is not a universal solution.

Community · Accepted Answer · 2023-11-17 19:42:58Z

0

You can do that using call_user_func_array(). It works wonders (and even with lambda functions since PHP 5.3).

edited Nov 17, 2023 at 19:42

CommunityBot

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answered Sep 23, 2009 at 17:09

Nicolas

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