how to simplify this multi-dimensions associative array?

Question

$arr1 = array(
1=>array(
 'name' => 'a',
 'phone'=> '110',
),
2=>array(
 'name' => 'b',
 'phone'=> '119',
),
3=>array(
 'name' => 'a',
 'phone'=> '119',
 ),
4=>array(
 'name' => 'b',
 'phone'=> '110',
),
);

I spent 3 hours to figure it out,and fails。I wanna merge the phone values to new arrays based on the name key values。 The result like this

$arr2 = array(
 1=>array(
 'name' => 'a',
 'phone'=> array(
 1=>'110',
 2=>'119',
 ),
 ),
 2=>array(
 'name' => 'b',
 'phone'=> array(
 1=>'110',
 2=>'119',
 ),
 )
);

It's not as easy as it looks.

• Barmar: Here's an answer that shows how to do it in Javascript: stackoverflow.com/questions/24302630/… The logic is the same in PHP, just minor syntax differences.

Answer 1

You need to loop through the array and make a new one.

code

<?php
/** store the results in here **/
$targetArray = [];
/** the data source **/
$sourceArray = [
 1 => [
 'name' => 'a',
 'phone'=> '110',
 ],
 2 => [
 'name' => 'b',
 'phone'=> '119',
 ],
 3 => [
 'name' => 'a',
 'phone'=> '119',
 ],
 4 => [
 'name' => 'b',
 'phone'=> '110',
 ]
];
foreach($sourceArray as $arr) {
 /** create key based off name **/
 $targetArray[$arr['name']]['name'] = $arr['name'];
 /** add phone numbers as they are found **/
 $targetArray[$arr['name']]['phone'][] = $arr['phone'];
}
/** reindex the array **/
$targetArray = array_values($targetArray);
/** see the result **/
var_dump($targetArray);

output

array(2) {
 [0]=>
 array(2) {
 ["name"]=>
 string(1) "a"
 ["phone"]=>
 array(2) {
 [0]=>
 string(3) "110"
 [1]=>
 string(3) "119"
 }
 }
 [1]=>
 array(2) {
 ["name"]=>
 string(1) "b"
 ["phone"]=>
 array(2) {
 [0]=>
 string(3) "119"
 [1]=>
 string(3) "110"
 }
 }
}

• Alfwed: if you replace sort by array_values i'll upvote you
• Jonathan: wrote it quickly without thinking, but yes that is definitely the better way.
• sfy: very illuminating and insightful, beautiful codes, thanks a lot. can't believe it can be done in such way.
• Jonathan: @Jacob glad I was able to help, don't forget to accept this answer if it's your chosen one :) thx.

Answer 2

Here is one solution:

// Use name as key to merge contact info.
foreach($arr1 as $contactInfo)
{
 $arr2[$contactInfo['name']]['name'] = $contactInfo['name'];
 $arr2[$contactInfo['name']]['phone'][] = $contactInfo['phone'];
}
// Go back to numeric indexes.
$arr2 = array_values($arr2);