Run throw array of associative array and find keys - php

Question

I have two arrays that look like this:
(this one is ordered by value_max)
$max_values = [
["name" => "john", "id" => 5, "value_max" => 500],
["name" => "john", "id" => 3, "value_max" => 200],
...
];
$min_values = [
["name" => "john", "id" => 5, "value_min" => 100],
["name" => "john", "id" => 3, "value_min" => 150],
...
];
And I need to have a final array like this:
(This one stills need to be ordered by value_max, so I assume I could just overwrite the first array with the calculations done with the second)
$max_and_difference_values = [
["name" => "john", "id" => 5, "value_max" => 500, "difference_value" => 400],
["name" => "john", "id" => 3, "value_max" => 200, "difference_value" => 50 ],
...
];
My question is pretty straight: What is the best/effective way to run through both first arrays and build the last one. Assuming that the size of the arrays can be of around 150 elements.

Answer 1

To avoid looping through all arrays repeatedly, index one array by the field you want to merge on, i.e. the 'id' key:
$second = array_combine(array_map(function ($i) { return $i['id']; }, $second_array), $second_array);
Then looping through the other and comparing the values is pretty easy:
$third = array();
foreach ($first_array as $i) {
$third[] = $i + array('difference_value' => $i['value_max'] - $second[$i['id']]['value_min']);
}
If it's guaranteed that both arrays will have exactly matching keys, you don't even need the first step and just go by already existing keys.

Answer 2

This will sort your array. So you can sort the second array.
<?php
$min_values = array(
array("name" => "john", "id" => 5, "value_min" => 100),
array("name" => "john", "id" => 3, "value_min" => 150),
);
function aasort (&$array, $key) {
$sorter=array();
$ret=array();
reset($array);
foreach ($array as $ii => $va) {
$sorter[$ii]=$va[$key];
}
asort($sorter);
foreach ($sorter as $ii => $va) {
$ret[$ii]=$array[$ii];
}
$array=$ret;
}
aasort($min_values,"id");
echo "<pre>";
print_r($min_values);
echo "</pre>";
?>
And then you can use the logic what Alessandro Minoccheri mentioned.
$arr = array();
for ($i=0; $i<count($first_array);$i++){
$arr['name'] = $first_array[$i]['name'];
$arr['id'] = $first_array[$i]['id'];
$arr['value_max'] = $first_array[$i]['value_max'];
$arr['difference_value'] = $first_array[$i]['value_max']-$second[$i['id']]['value_max'] ;
}

Answer 3

As you have not shared how the second array with the minimum values is ordered (in itself and relative to the maximum values array), I'd say, index the minimum values by the id entry and then do the calculation in a second iteration. It should be fast enough, 150 elements is just "nothing":
$max_values = [
["name" => "john", "id" => 5, "value_max" => 500],
["name" => "john", "id" => 3, "value_max" => 200],
];
$min_values = [
["name" => "john", "id" => 5, "value_min" => 100],
["name" => "john", "id" => 3, "value_min" => 150],
];
$min_values_by_id = [];
foreach($min_values as $min) {
$min_values_by_id[$min['id']] = $min['value_min'];
}
$max_and_difference_values = $max_values;
foreach($max_and_difference_values as &$entry)
{
$entry['difference_value'] = $entry['value_max'] - $min_values_by_id[$entry['id']];
}
unset($entry);
print_r($max_and_difference_values);
This is just a straight forward example, nothing fancy. Demo

Answer 4

the following works for me. I'm not a PHP expert though, i.e. I'm not so familiar with cloning (note the empty clone array). Note that it only copies existing properties (if one array does contain a min_value and another does only contain a some other key)
In essence
function convertArr( $arr ) {
// Easy referencing without having to search through the arrays more than once for a matching id
$new_arr = array();
foreach( $arr as $array ) {
$new_arr[ $array['id'] ] = cloneArr( $array );
}
return $new_arr;
}
function merge( $arr1, $arr2 ) {
$convertedArr1 = convertArr( $arr1 );
$convertedArr2 = convertArr( $arr2 );
$arr = array();
// Based on the ordered array
foreach( $convertedArr1 as $array ) {
$id = $array['id'];
$tempArr = array();
foreach( $convertedArr1[ $id ] as $k => $v ) {
$tempArr[ $k ] = $v;
}
foreach( $convertedArr2[ $id ] as $k => $v ) {
$tempArr[ $k ] = $v;
}
array_push( $arr, $tempArr );
}
return $arr;
}
Full example:
<?php
//$arr1 = [ ["name" => "john", "id" => 5, "value_max" => 500], ["name" => "john", "id" => 3, "value_max" => 200] ];
//$arr2 = [ ["name" => "john", "id" => 5, "value_min" => 100], ["name" => "john", "id" => 3, "value_min" => 150] ];
$arr1 = array(
array( "name" => "john", "id" => 5, "value_max" => 500 ),
array( "name" => "john", "id" => 3, "value_max" => 200 )
);
$arr2 = array(
array( "name" => "john", "id" => 5, "value_min" => 100 ),
array( "name" => "john", "id" => 3, "value_min" => 150 )
);
function neatPrint( $arr ) {
echo "<pre>";
print_r( $arr );
echo "</pre>";
}
echo "<h2>Before</h2>";
neatPrint( $arr1 );
neatPrint( $arr2 );
echo "<hr/>";
function cloneArr( $old ) {
// I dunno how to properly clone
return $old;
}
function convertArr( $arr ) {
// Easy referencing without having to search through the arrays more than once for a matching id
$new_arr = array();
foreach( $arr as $array ) {
$new_arr[ $array['id'] ] = cloneArr( $array );
}
return $new_arr;
}
function merge( $arr1, $arr2 ) {
$convertedArr1 = convertArr( $arr1 );
$convertedArr2 = convertArr( $arr2 );
$arr = array();
// Based on the ordered array
foreach( $convertedArr1 as $array ) {
$id = $array['id'];
$tempArr = array();
neatPrint( $convertedArr1[ $id ] );
neatPrint( $convertedArr2[ $id ] );
foreach( $convertedArr1[ $id ] as $k => $v ) {
$tempArr[ $k ] = $v;
}
foreach( $convertedArr2[ $id ] as $k => $v ) {
$tempArr[ $k ] = $v;
}
array_push( $arr, $tempArr );
}
echo "<h2>Result</h2>";
return $arr;
}
echo "<h2>Loopthrough</h2>";
neatPrint( merge( $arr1, $arr2 ) );
?>
Let me know what you think :-)

Answer 5

if the element are in order try this code:
$arr = array();
for ($i=0; $i<count($first_array);$i++){
$arr['name'] = $first_array[$i]['name'];
$arr['id'] = $first_array[$i]['id'];
$arr['value_max'] = $first_array[$i]['value_max'];
$arr['difference_value'] = $first_array[$i]['value_max']-$second[$i['id']]['value_max'] ;
}