PHP Adding multiple associative arrays to new array based on key - php

Question

I have a few associative arrays that I need to merge together based on there key.
so:
array1:
[person1] => tony
[person2] => sandra
array2:
[person1] => london
[person2] => paris
needs to be :
array 3
[person1] => tony , london
[person2] => sandra , paris
The issue I'm having though is that the key could be any value , so it could be 'person1' or it could be 'hairyOtter' and the array is of varaible size.

Answer 1

Assuming, that every is not multi-dimensional
$merged = array_merge_recursive($array1, $array2);
foreach ($merged as &$entry) {
if (is_array($entry)) {
$entry = implode(', ', $entry);
}
}
The idea is, that array_merge_recursive() creates a new array, if it find two values with the same key. Everything else stays untouched.

Answer 2

I'm sure there are more efficient ways to accomplish this, but for now, this works:
<?php
function combine( $keys, $first, $second ) {
$args = func_get_args( );
$keys = array_shift( $args );
$arrays = $args;
$result = array( );
foreach( $keys as $key ) {
foreach( $arrays as $array ) {
if( isset( $array[$key] ) ) {
$result[$key][] = $array[$key];
}
}
}
return $result;
}
$first = array(
'person1' => 'tony',
'person2' => 'sandra'
);
$second = array(
'person1' => 'london',
'person2' => 'paris'
);
/**
* To make sure you get *every* key out of both arrays.
*/
$keys = array_unique( array_merge( array_keys( $first ), array_keys( $second ) ) );
$combined = combine( $keys, $first, $second );
var_dump( $combined );

Answer 3

Two loops should do it. Iterate over each of array1 and array2, initialising array3's keys as you go to an array, and pushing into that array. Here's the first loop
$array3 = array();
foreach (array_keys($array1) as $key) {
if(!array_key_exists($key, $array3)) {
$array3[$key] = array();
}
array_push($array3[$key], $array1[$key]);
}

Answer 4

$array1 = array('a' => 1, 'b' => 2);
$array2 = array('a' => 3, 'b' => 4, 'c' => 5);
foreach ($array1 as $k => $v) {
$tArray[$k][] = $v;
}
foreach ($array2 as $k => $v) {
$tArray[$k][] = $v;
}
foreach ($tArray as $k => $v) {
$tArray[$k] = implode(',',$tArray[$k]);
}

Answer 5

I would create a multi-dimensional array instead, unless there is a specific reason you can't use one. This way, you would have an array that looks like:
Array
(
[Person1] => Array
(
[Name] => Tony
[City] => London
)
[Person2] => Array
(
[Name] => Sandra
[City] => Paris
)
)