Combine inner arrays in a multi-dimensional array - PHP - php

Question

I have a two-dimensional array:
array(
array(
'Friend',
'Amigo',
'',
''
),
array(
'Friend',
'',
'Fraund',
''
),
array(
'Thanks',
'Gracias',
'',
''
),
array(
'Thanks',
'',
'Danke',
''
)
);
Basically, I need to combine inner arrays when they have the same values in a corresponding order. For example, 'friend' and 'thanks' in a current example. Output should be:
array(
array(
'Friend',
'Amigo',
'Fraund',
''
),
array(
'Thanks',
'Gracias',
'Danke',
''
)
);
Thus, the empty element needs to be overwritten by the corresponding element which has got some value. Cannot figure out how to do it with array_merge.

Answer 1

You could use array_reduce() like this:
$result = array_values(array_reduce($a, function(array &$final, $current) {
$key = $current[0];
if (isset($final[$key])) {
// replace items that are not an empty string
$final[$key] = array_replace($final[$key], array_filter($current, 'strlen'));
} else {
$final[$key] = $current;
}
return $final;
}, []));
The reduce operation creates an array whereby the first word of each array is used as the key; array_replace() updates existing values with new ones if the string is not empty.
The end result is then pulled through array_values() to get rid of the temporary keys that were used during the reduce operation.

Answer 2

Well, I'd go about it like this
$final_array = array();
$original_array = array(
array(
'Friend',
'Amigo',
'',
''
),
array(
'Friend',
'',
'Fraund',
''
),
array(
'Thanks',
'Gracias',
'',
''
),
array(
'Thanks',
'',
'Danke',
''
)
);
$friends_array = array();
foreach($original_array[0] as $row) {
if($row != "") {
array_push($friends_array, $row);
}
}
foreach($original_array[1] as $row) {
if($row != "" && !in_array($row, $friends_array)) {
array_push($friends_array, $row);
}
}
$thanks_array = array();
foreach($original_array[2] as $row) {
if($row != "") {
array_push($thanks_array, $row);
}
}
foreach($original_array[3] as $row) {
if($row != "" && !in_array($row, $thanks_array)) {
array_push($thanks_array, $row);
}
}
array_push($final_array, $friends_array, $thanks_array);
You do have a very specific request. Rather odd tbh.

Answer 3

Iterate the array, add the values to a new array (indexed by the 1st element in the internal arrays), then use array_values to get your desired output (or leave it indexed as is, which may be beneficial for further data access):
$out = [];
foreach ($input as $val) {
$key = $val[0];
foreach ($val as $item) {
if(!empty($item) && $item !=$key){
$out[$key][]=$item;
}
}
if(!in_array($key, $out[$key])) $out[$key][]=$key;
}
$out = array_values($out);
var_dump($out);
Live working example:
http://codepad.viper-7.com/EoRhh2

Answer 4

in php you can use
array_unique($arr1,$arr2);
or
array_merge($arr1,$arr2);
But in your condition you ahve a single array which you have to split into different arrays
$mainArary = array(
array(
'Friend',
'Amigo',
'',
''
),
array(
'Friend',
'',
'Fraund',
''
),
array(
'Thanks',
'Gracias',
'',
''
),
array(
'Thanks',
'',
'Danke',
''
)
);
$first_array = null;
$second_array = null;
$i = 0;
foreach($mainArray[0] as $arr){
if($i < 2){
if($prev_array == null){
$prev_array = $arr;
} else {
$prev_array = array_merge($prev_array,$arr);
} } else {
if($second_array == null){
$second_array = $arr;
} else {
$second_array = array_merge($second_array ,$arr);
}
}
}
print_r($prev_array);
print_r($second_array);
Here is your desired output.