How to merge two array if one item exist in both array? - php

Question

I want to expand my city array with post code value.
If the city_postcode array contain city array name record then push postcode value into city array. That's what i want to achive somehow.
city array:
Array
(
[0] => Array
(
[id] => 1
[city] => Budapest
[population] => 1700000
)
[1] => Array
(
[id] => 2
[city] => Szeged
[population] => 160000
)
)
city_postcode array:
Array
(
[0] => Array
(
[name] => Budapest
[post_code] => 12345
)
[1] => Array
(
[name] => Szeged
[post_code] => 33356
)
)
The result I want:
Array
(
[0] => Array
(
[id] => 1
[city] => Budapest
[population] => 1700000
[post_code] => 12345
)
[1] => Array
(
[id] => 2
[city] => Szeged
[population] => 160000
[post_code] => 33356
)
)

Answer 1

If you can rely on the cities and post codes to be equal in length and sorted, you could just do something like this:
<?php
$cities = array(
array("id"=>1,"city"=>"Budapest","Population"=>"1700000"),
array("id"=>2,"city"=>"Szeged","Population"=>"160000")
);
$cityPostCode = array(
array("name"=>"Budapest","post_code"=>12345),
array("name"=>"Szeged","post_code"=>33356)
);
for($i = 0; $i < count($cities); $i++){
$cities[$i]['post_code'] = $cityPostCode[$i]['post_code'];
}
print_r($cities);
Other wise you could do something more dyanmic like:
function _parsePostCode($targetName,$targetArr){
foreach($targetArr as $el){
if($el['name'] == $targetName){
return $el['post_code'];
}
}
return false;
}
for($i = 0; $i < count($cities); $i++){
$cities[$i]['post_code'] = _parsePostCode($cities[$i]['city'],$cityPostCode);
}
print_r($cities);

Answer 2

As an alternative you can use 'reference' PHP in foreach loop as follows
$city = array(
0 => array(
'id' => 1,
'city' => "Budapest",
'population' => 1700000
),
1 => array(
'id' => 2,
'city' => "Szeged",
'population' => 160000
)
);
$city_postcode = array(
0 =>array(
'name' => 'Budapest',
'post_code' => 12345
),
1 => array(
'name' => 'Szeged',
'post_code' => 33356
)
);
foreach ($city as $ckey => &$cval) {
$cval['post_code'] = $city_postcode[$ckey]['post_code'];
}
unset($cval);
var_dump($city);

Answer 3

You can use this simple approach :
<?php
$city = array(
0 => array(
'id' => 1,
'city' => "Budapest",
'population' => 1700000
),
1 => array(
'id' => 2,
'city' => "Szeged",
'population' => 160000
)
);
$city_postcode = array(
0 => array(
'name' => 'Budapest',
'post_code' => 12345
),
1 => array(
'name' => 'Szeged',
'post_code' => 33356
)
);
function apply_post_code(&$item, $key, $postcode)
{
$item['post_code'] = $postcode[ $key ][ 'post_code' ];
}
array_walk($city, 'apply_post_code', $city_postcode);
var_dump($city);
Note that the $city variable has been passes by reference