Most efficient way to index a returned array?

Question

function returnsAnArray ()
{
  return array ('test');
}

echo returnsAnArray ()[0];

generates a syntax error in PHP. What's the most efficient way to directly obtain an element from a returned array without assigning the result to a temp variable?

Answer 1

This will work if there is only one member in the array:

 <?php
 echo current(returnsAnArray());
 ?>

Answer 2

You could do this for an indexed array of unknown length.

foreach ( returnsAnArray() as $item )
  echo $item;

Answer 3

Here's one way, using the list language construct

function returnsAnArray ()
{
  return array ('test');
}

list($foo)=returnsAnArray();

You could grab a sequence of elements from an offset by combining this with array_slice

list($third,$fourth,$fifth)=array_slice(returnsAnArray(), 2, 3);

Answer 4

I ask myself why one would like to avoid creating a temporary variable for a returned array. Why don't you just return one value instead of an whole array? Maybe you'll have to overthink your program logic.

Or is it a performance/memory issue? Consider using references instead of always creating a new array object and returning it.

Answer 5

Define a new function for returning a specific index from an array.

function arr_index($arr, $i) { return $arr[$i]; }

You might want to add some error and type checking there.

And then use it like this:

echo arr_index(returnsAnArray(), 0);

Happy Coding :)

Answer 6

Another option:

<?php
echo reset(functionThatReturnsAnArray());
?>

Similar thread: http://stackoverflow.com/questions/68711/php-can-i-reference-a-single-member-of-an-array-that-is-returned-by-a-function

Answer 7

For regular numerically indexed arrays, where func() returns such an array and $n is the index you want:

array_pop(array_slice(func(),$n,1));

For associative arrays (e.g. strings or other things as keys), or numeric arrays that aren't numbered and complete from 0..n, it's a little more convoluted. Where $key is the key you want:

array_pop(array_intersect_keys(func(),Array($key => ""));

This would also work for the first case.