Create an associative array only from other array values ​​- PHP

Question

I have a simple array that is always followed by a key:

Array ( [0] => x [1] => foo [2] => y [3] => bar ) 

which I would like to convert to associative:

 Array ( [x] => foo [y] => bar ) 

What is the easiest and most elegant way to do this?

Answer 1

Memory efficiency and fewer calculations.

If the $ input array has an odd number of values, the last value will be NULL.

 $result = array(); while (count($input)) { $result[array_shift($input)] = array_shift($input); } 

Answer 2

I do not know how effective this is, but:

 $newArray = array(); foreach(array_chunk($array, 2) as $keyVal){ list($key, $val) = $keyVal; $newArray[$key] = $val; } 

DEMO: http://codepad.org/VF8qHAhQ

Answer 3

 $ar = Array("x","foo","y","bar"); $assoc = Array(); for($i=0;$i<count($ar);$i+=2){$assoc[$ar[$i]]=$ar[$i+1];} print_r($assoc); 

Output: array ([x] => foo [y] => bar)

Answer 4

I'll start with a simple loop

 $arr = array( 'x', 'foo', 'y', 'bar' ); $result = array(); $end = count($arr); for ($i = 0; $i+1 < $end; $i+=2) { $result[$arr[$i]] = $arr[$i+1]; } var_dump($result); 

Output:

 array(2) { ["x"]=> string(3) "foo" ["y"]=> string(3) "bar" } 

Answer 5

Assuming you want key / value pairs to be in each / other pattern, you can use:

 $data = array('x', 'foo', 'y', 'bar', 'z'); $new = array(); $end = count($data); for ($i = 0; $i < $end; $i += 2) { $new[$data[$i]] = (isset($data[$i + 1]) ? $data[$i + 1] : ''); } print_r($new); 

It gives:

 Array ( [x] => foo [y] => bar [z] => ) 

This will jump to your data list and set the first value as the key and the next as the value. If there is no “next” value (that is, the Finite element in the original array, which is not divisible by 2), it is empty.

A caveat to this approach is that if the same “key” is examined more than once, it will be overwritten. This can be circumvented by adding if (isset($new[$data[$i]])) continue; as the first line in the loop.

Answer 6

What about:

 $data = array('x','foo','y','bar'); $i = 0; $n = count($data) $newData = array(); while($i < $n) { $newData[$data[$i]] = $data[++$i]; }