Merge complex array php

Question

I have a site developed in php (codeigniter) and I want to merge some array with same structure. This is the constructor of my array:

$first = array();
$first['hotel'] = array();
$first['room'] = array();
$first['amenities'] = array();

/*
Insert data into $first array
*/

$second = array();
$second['hotel'] = array();
$second['room'] = array();
$second['amenities'] = array();

/*
Insert data into $second array
*/

After insert data I want to merge this array but the problem is that I have subarray inside it and I want to create a unique array like that:

$total = array();
$total['hotel'] = array();
$total['room'] = array();
$total['amenities'] = array();

This is the try to merge:

$total = array_merge((array)$first, (array)$second);

In this array I have only the $second array why?

Answer 1

Use the recursive version of array_merge called array_merge_recursive.

Answer 2

It seems like array_merge doesn't do what you think it does: "If the input arrays have the same string keys, then the later value for that key will overwrite the previous one." Try this:

function merge_subarrays ($first, $second)
  $result = array();
  foreach (array_keys($first) as $key) {
    $result[$key] = array_merge($first[$key], $second[$key]);
  };
  return $result;
};

Then call it as:

$total = merge_subarrays($first, $second);

and, if I've correctly understood your question, $total will contain the result you're looking for.

Answer 3

There is no standard way of doing it, you just have to do something like:

<?php
$first = array();
$first['hotel'] = array('hello');
$first['room'] = array();
$first['amenities'] = array();

/*
Insert data into $first array
*/

$second = array();
$second['hotel'] = array('world');
$second['room'] = array();
$second['amenities'] = array();

$merged = array();
foreach( $first as $key => $value )
{
    $merged[$key] = array_merge( $value, $second[$key] );
}

print_r( $merged );