Counting blanks when merging assoctiative arrays - php

Question

I'm trying to merge these 2 arrays
$arr1 = array('a' => "1", 'b' => "2", 'c' => "3");
$arr2 = array('a' => "9", 'b' => "8", 'd' => "7");
into an array that looks like this
$arr1 = array(
'a' => array("1", "9"),
'b' => array("2", "8"),
'c' => array("3", ""),
'd' => array("", "7")
);
The tricky part is the blanks. I need to preserve them in place.
Thanks

Answer 1

function merge()
{
$array_of_arrays = func_get_args();
//get all the unique keys
$final_array_keys = array_keys( call_user_func_array( "array_merge", $array_of_arrays ) );
//make final array
$final_array = array();
foreach( $final_array_keys as $key ) {
foreach( $array_of_arrays as $current_array ) {
$final_array[$key][] = array_key_exists( $key, $current_array ) ? $current_array[$key] : "";
}
}
return $final_array;
}

Answer 2

Try this:
$arr1 = array('a' => "1", 'b' => "2", 'c' => "3");
$arr2 = array('a' => "9", 'b' => "8", 'd' => "7");
$keys = array();
$merged = array()
for($arr1 as $key=>$val)
{
array_push($keys,$key);
}
for($arr2 as $key=>$val)
{
array_push($keys,$key);
}
for($key in keys)
{
$merged[$key] = array("","");
if(isset($arr1[$key])) $merged[$key][0] = $arr1[$key];
if(isset($arr2[$key])) $merged[$key][1] = $arr2[$key];
}

Answer 3

foreach (array_merge($arr1, $arr2) as $key => $val)
{
$result[$key] = array("{$arr1[$key]}", "{$arr2[$key]}");
}
var_dump($result);

Answer 4

here's my suggestion. It'll combine an arbitrary number of arrays according to what you described.
error_reporting(E_ALL | E_STRICT);
header('Content-Type: text/plain');
$arr1 = array('a' => "1", 'b' => "2", 'c' => "3");
$arr2 = array('a' => "9", 'b' => "8", 'd' => "7");
$arr = combine($arr1, $arr2);
print_r($arr);
function combine() {
$keys = array();
foreach (func_get_args() as $arr) {
if (is_array($arr)) {
$keys += $arr;
}
}
$keys = array_keys($keys);
$values = array_pad(array(), count($keys), array());
$ret = array_combine($keys, $values);
foreach (func_get_args() as $arr) {
foreach ($keys as $k) {
$v = array_key_exists($k, $arr) ? $arr[$k] : '';
array_push($ret[$k], $v);
}
}
return $ret;
}
Output:
Array
(
[a] => Array
(
[0] => 1
[1] => 9
)
[b] => Array
(
[0] => 2
[1] => 8
)
[c] => Array
(
[0] => 3
[1] =>
)
[d] => Array
(
[0] =>
[1] => 7
)
)

Answer 5

I like cletus's approach, so I've just made sure it works :)
function combine() {
$keys = array();
foreach (func_get_args() as $arr) {
if (is_array($arr)) {
$keys = array_merge($keys, array_keys($arr));
}
}
$keys = array_unique($keys);
$values = array_pad(array(), count($keys), array());
$ret = array_combine($keys, $values);
foreach (func_get_args() as $arr) {
foreach ($keys as $k) {
$v = '';
if (array_key_exists($k, $arr)){
$v = $arr[$k];
}
array_push($ret[$k], $v);
}
}
return $ret;
}