PHP combines arrays and retains key values. Example sharing

This article mainly shares with you an implementation method of merging arrays and retaining key values ​​​​in PHP. It has a good reference value and I hope it can help everyone.

php merges arrays, generally using the array_merge method.

array_merge — Merge one or more arrays

array array_merge ( array $array1 [, array $... ] )

array_merge Merges the cells of one or more arrays. The values ​​in one array are appended to the previous array and returned as the result. array.

If the input array has the same string key name, the value after the key name will overwrite the previous value. However, if the array contains numeric keys, the latter will not overwrite the original value, but will be appended to it.

If only an array is given and the array is numerically indexed, the key names are re-indexed in a consecutive manner.

Example 1, the array uses string key names, the same key name will be overwritten by the following one

<?php
$arr1 = array(&#39;name&#39;=>&#39;fdipzone&#39;);
$arr2 = array(&#39;name&#39;=>&#39;terry&#39;);
$result = array_merge($arr1, $arr2);
print_r($result);
?>

Output:

Array
(
 [name] => terry
)

Example 2, the array uses numeric key names, the same key name will not be overwritten, and the key name will be re-indexed

<?php
$arr1 = array(0=>&#39;fdipzone&#39;,1=>&#39;terry&#39;);
$arr2 = array(0=>&#39;php&#39;,1=>&#39;python&#39;);
$result = array_merge($arr1, $arr2);
print_r($result);
?>

Output:

Array
(
 [0] => fdipzone
 [1] => terry
 [2] => php
 [3] => python
)

Due to work needs, the answers to the two parts of the multiple-choice questions in the questionnaire need to be combined. The answers to each part are arrays (key=>value), the key is the question number, and the value is the answer, and the question numbers in the two parts are not the same. There are duplicates.

Use array_merge to merge the two parts of the answer

<?php
$form_data1 = array(11=>&#39;A&#39;,12=>&#39;B&#39;,13=>&#39;C&#39;,14=>&#39;D&#39;);
$form_data2 = array(25=>&#39;B&#39;,26=>&#39;A&#39;,27=>&#39;D&#39;,28=>&#39;C&#39;);
$result = array_merge($form_data1, $form_data2);
print_r($result);
?>

Output:

Array
(
 [0] => A
 [1] => B
 [2] => C
 [3] => D
 [4] => B
 [5] => A
 [6] => D
 [7] => C
)

Use array_merge to merge, because the question number (key) is a number, so the key name will be re-indexed, resulting in the question The number cannot be reserved.

Method to merge arrays and keep key values:

<?php
$form_data1 = array(11=>&#39;A&#39;,12=>&#39;B&#39;,13=>&#39;C&#39;,14=>&#39;D&#39;);
$form_data2 = array(25=>&#39;B&#39;,26=>&#39;A&#39;,27=>&#39;D&#39;,28=>&#39;C&#39;);
$result = $form_data1 + $form_data2;
print_r($result);
?>

Output:

Array
(
 [11] => A
 [12] => B
 [13] => C
 [14] => D
 [25] => B
 [26] => A
 [27] => D
 [28] => C
)

Use "+" operator merges arrays and can retain the key values ​​of the array. If the merged array contains the same key value, the later one will not overwrite the previous key value (the previous one takes precedence).

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