Add item to array of arrays based on id - php

Question

I have an array of arrays set up like so. There are a total of 10 arrays but I will just display the first 2. The second column has a unique id of between 1-10 (each only used once).
Array
(
[0] => Array
(
[0] => User1
[1] => 5
)
[1] => Array
(
[0] => User2
[1] => 3
)
)
I have another array of arrays:
Array
(
[0] => Array
(
[0] => 3
[1] => 10.00
)
[1] => Array
(
[0] => 5
[1] => 47.00
)
)
where the first column is the id and the second column is the value I want to add to the first array.
Each id (1-10) is only used once. How would I go about adding the second column from Array#2 to Array#1 matching the ID#?

Answer 1

There are tons of ways to do this :) This is one of them, optimizing the second array for search and walking the first one:
Live example
<?
$first_array[0][] = 'User1';
$first_array[0][] = 5;
$first_array[1][] = 'User2';
$first_array[1][] = 3;
$secnd_array[0][] = 3;
$secnd_array[0][] = 10.00;
$secnd_array[1][] = 5;
$secnd_array[1][] = 47.00;
// Make the user_id the key of the array
foreach ($secnd_array as $sca) {
$searchable_second_array[ $sca[0] ] = $sca[1];
}
// Modify the original array
array_walk($first_array, function(&$a) use ($searchable_second_array) {
// Here we find the second element of the first array in the modified second array :p
$a[] = $searchable_second_array[ $a[1] ];
});
// print_r($first_array);

Answer 2

Assuming that 0 will always be the key of the array and 1 will always be the value you'd like to add, a simple foreach loop is all you need.
Where $initial is the first array you provided and $add is the second:
<?php
$initial = array(array("User1", 5),
array("User2", 3));
$add = array(
array(0, 10.00),
array(1, 47.00));
foreach ($add as $item) {
if (isset($initial[$item[0]])) {
$initial[$item[0]][] = $item[1];
}
}
printf("<pre>%s</pre>", print_r($arr1[$item[0]], true));

Answer 3

I don't know if I got you right, but I've come up with a solution XD
<?php
$array_1 = array(
0 => array(
0 => 'ID1',
1 => 5
),
1 => array(
0 => 'ID2',
1 => 3
)
);
$array_2 = array(
0 => array(
0 => 3,
1 => 10.00
),
1 => array(
0 => 5,
1 => 47.00
)
);
foreach($array_1 as $key_1 => $arr_1){
foreach($array_2 as $key_2 => $arr_2){
if($arr_2[0] == $arr_1[1]){
$array_1[$key_1][2] = $arr_2[1];
}
}
}
var_dump($array_1);
?>
Demo: https://eval.in/201648
The short version would look like this:
<?php
$array_1 = array(array('ID1',5),array('ID2',3));
$array_2 = array(array(3,10.00),array(5,47.00));
foreach($array_1 as $key => $arr_1){
foreach($array_2 as$arr_2){
if($arr_2[0] == $arr_1[1]){
$array_1[$key][2] = $arr_2[1];
}
}
}
var_dump($array_1);
?>
Demo: https://eval.in/201649
Hope that helps :)

Answer 4

A quick and dirty way just to show you one of the more self-explaining ways to do it :)
$users = array(
0 => array(
0 => 'User1',
1 => 123
),
1 => array(
0 => 'User2',
1 => 456
)
);
$items = array(
0 => array(
0 => 123,
1 => 'Stuff 1'
),
1 => array(
0 => 456,
1 => 'Stuff 2'
)
);
foreach($items as $item){
foreach($users as $key => $user){
if($item[0] == $user[1])
array_push($users[$key], $item[1]);
}
}