Merge two associative arrays by same key

问题

I have two associative array having one value in common, like

ARRAY 1(
  [0]=>
  array(2) {
    ["ID"]=> "AAAA"
    ["Name"]=> "Apple"
  }
  [1]=>
  array(2) {
    ["ID"]=> "BBBB"
    ["Name"]=> "Avocado"
  }
  [3]=>
  array(2) {
    ["ID"]=> "CCCC"
    ["Name"]=> "Banana"
  }
)



Array2 (
  [0]=>
  array(4) {
    ["ID"]=> "AAAA"
    ["Taste"]=> "Yumi"
    ["Location"]=> "France"
    ["Price"]=> "Cheap"
  }
  [1]=>
  array(4) {
    ["ID"]=> "CCCC"
    ["Taste"]=> "Yumi"
    ["Location"]=> "Africa"
    ["Price"]=> "Cheap"
  }
  [3]=>
  array(4) {
    ["ID"]=> "BBBB"
    ["Taste"]=> "Yumi"
    ["Location"]=> "America"
    ["Price"]=> "Expansive"
  }
  [3]=>
  array(4) {
    ["ID"]=> "HZGA"
    ["Taste"]=> "Berk"
    ["Location"]=> "Moon"
    ["Price"]=> "Expansive"
  }

)

I would like to merge them both by their ID. A simple merge isn't possible because they arn't sorted, have 40.000 + values and don't have the same size.

I planned to use a double foreach, and create a third array were the ID was common, I dropped the idea. Since having to parse 40.000 values in the first array for each of the 40.000 values from the second array take too long.

Is there some solution ? I would like to having it look like this at final :

ArrayFinal (
  [0]=>
  array(4) {
    ["ID"]=> "AAAA"
    ["Name"]=> "Apple"
    ["Taste"]=> "Yumi"
    ["Location"]=> "France"
    ["Price"]=> "Cheap"
  }
  [1]=>
  array(4) {
    ["ID"]=> "CCCC"
    ["Name"]=> "Banana"
    ["Taste"]=> "Yumi"
    ["Location"]=> "Africa"
    ["Price"]=> "Cheap"
  }
  [3]=>
  array(4) {
    ["ID"]=> "BBBB"
    ["Name"]=> "Avocado"
    ["Taste"]=> "Yumi"
    ["Location"]=> "America"
    ["Price"]=> "Expansive"
  }
)

回答1:

You cannot avoid to loop. But foreach is pretty fast. Tested on an array of 50.000 and it took 0.04 seconds.

What this wil do is:

create a TMP array
get the KEY and ID values from ARRAY1
put them as 'ID'=>key in the TMP array
loop ARRAY2, get the ID
look up the corresponding ID in TMP
get the key from ARRAY1
merge ARRAY1 and ARRAY2

You'll end up with ARRAY1 having the data from ARRAY2

$ar1=[...]; //original array 1
$ar2=[...]; //original array 2

// get ID=> key pairs
$kv=[];
foreach($ar1 as $k => $v){
    $kv[ $v['id'] ] = $k;
    }

// loop ARRAY2
foreach($ar2 as $k => $v){
    if( array_key_exists( $v['id'] , $kv ) ){
        $ar1[ $kv[$v['id']] ] = array_merge( $ar1[$kv[$v['id']]] , $ar2[$k] );
        }
    }

回答2:

https://eval.in/1011901

 <?php 

$a = [['ID'=> 'TOTO'], ['ID' => 'TATA']];
$b = [['ID' => 'TATA', 'RA' => 'T'], ['ID' => 'TOTO', 'COUCOU' => 2]];

$final = [];

foreach($a as $c){
  if(!isset($final[$c['ID']])){
    $final[$c['ID']] = $c;
  }else{
    $final[$c['ID']] += $c;
  }
}
foreach($b as $c){
  if(!isset($final[$c['ID']])){
    $final[$c['ID']] = $c;
  }else{
    $final[$c['ID']] += $c;
  }
}
var_dump(array_values($final));

OUTPUT

array(2) {
  [0]=>
  array(2) {
    ["ID"]=>
    string(4) "TOTO"
    ["COUCOU"]=>
    int(2)
  }
  [1]=>
  array(2) {
    ["ID"]=>
    string(4) "TATA"
    ["RA"]=>
    string(1) "T"
  }
}

来源：https://stackoverflow.com/questions/50587034/merge-two-associative-arrays-by-same-key

标签

php

associative-array