In PHP, you may want to merge different arrays and treat them as a single array. This is useful, for example, when integrating data retrieved from a database or user input.
To merge arrays, you primarily use the following three functions:
- array_merge: Simply concatenates arrays.
- array_push: Adds new values to an existing array.
- array_merge_recursive: Merges arrays while preserving keys in associative arrays.
In this article, we will explain the behavior and specific output results when using each function in a way that even beginners can understand. Learn the “best practices for array manipulation” in PHP development!
Prepared Array Data
The following indexed arrays and associative arrays were prepared.
// Indexed arrays
$arry1 = array('A','B','C');
$arry2 = array('D','E','F');
// Associative arrays
$rensoarry1 = array(
'no' => 1,
'sei' => 'yamada',
'mei' => 'taro',
'sex' => 'men',
'todofuken' => 'tokyo'
);
$rensoarry2 = array(
'no' => 2,
'sei' => 'suzuki',
'mei' => 'ziro',
'sex' => 'women',
'city' => 'yokohama'
);
Output Result of Merging Using array_merge
array_merge for Indexed Arrays
print_r(array_merge($arry1,$arry2));
The output result of array_merge for indexed arrays is that $arry2 is appended to the end of $arry1.
Array
(
［0] => A
［1] => B
［2] => C
［3] => D
［4] => E
［5] => F
)
array_merge for Associative Arrays
print_r(array_merge($rensoarry1,$rensoarry2));
The output result of array_merge for associative arrays is:
If the keys are the same, $rensoarry2 overwrites $rensoarry1. If the keys are different, they are added.
Array
(
[no] => 2
[sei] => suzuki
[mei] => ziro
[sex] => women
[todofuken] => tokyo
[city] => yokohama
)
Output Result of Merging Using array_push
array_push for Indexed Arrays
array_push($arry1,$arry2);
print_r($arry1);
The output result of array_push for indexed arrays is that $arry2 is added as a single index at the end of $arry1.
Array
(
［0] => A
［1] => B
［2] => C
［3] => Array
(
［0] => D
［1] => E
［2] => F
)
)
array_push for Associative Arrays
array_push($rensoarry1,$rensoarry2);
print_r($rensoarry1);
The output result of array_push for associative arrays is that $rensoarry2 is added at the end of $rensoarry1 as a single index [0].
Array
(
[no] => 1
[sei] => yamada
[mei] => taro
[sex] => men
[todofuken] => tokyo
［0] => Array
(
[no] => 2
[sei] => suzuki
[mei] => ziro
[sex] => women
[city] => yokohama
)
)
Output Result of Merging Using array_merge_recursive
array_merge_recursive for Indexed Arrays
print_r(array_merge_recursive($arry1, $arry2));
The output result of array_merge_recursive for indexed arrays is the same as array_merge, where $arry2 is appended to the end of $arry1.
Array
(
［0] => A
［1] => B
［2] => C
［3] => D
［4] => E
［5] => F
)
array_merge_recursive for Associative Arrays
print_r(array_merge_recursive($rensoarry1, $rensoarry2));
The output result of array_merge_recursive for associative arrays is:
Each key is grouped and output as arrays.
array_merge_recursive is a convenient merging function when working with associative arrays.
Array
(
[no] => Array
(
［0] => 1
［1] => 2
)
[sei] => Array
(
［0] => yamada
［1] => suzuki
)
[mei] => Array
(
［0] => taro
［1] => ziro
)
[sex] => Array
(
［0] => men
［1] => women
)
[todofuken] => tokyo
[city] => yokohama
)
Page Showing Output Results of Merging Arrays Using PHP’s array_merge, array_push, and array_merge_recursive
You can also check the page “Output results of merging arrays using PHP’s array_merge, array_push, and array_merge_recursive” from the link below.
Page showing output results of merging arrays using PHP’s array_merge, array_push, and array_merge_recursive
Summary
Each array merging function should be used according to its characteristics.
array_merge is suitable for simple array concatenation, and array_push is convenient when you want to add a single new element.
On the other hand, array_merge_recursive is suitable for complex merging of associative arrays. Choose according to your development needs and write efficient code!
*Please use at your own risk if reusing.
