Create a 'results' array based on comparison of two two-dimensional arrays? - php

Question

I have two two-dimensional arrays I'd liked to compare to one another:
$array1
Array
(
[0] => Array
(
[A] => GB
[B] => Harry
[C] => British Army
[D] => Eton College
[E] => Cressida Bonas
)
[1] => Array
(
[A] => GB
[B] => William
[C] => Royal Air Force
[D] => Eton College
[E] => Catherine Middleton
)
)
$array2
Array
(
[0] => Array
(
[A] => GB
[B] => Harry
[C] => British Army
[D] => Eton College
[E] => Cressida Bonas
)
[1] => Array
(
[A] => GB
[B] => James
[C] => British Army
[D] => Millfield
[E] => Unknown
)
)
And produce a boolean true/false results array as follows if any of the child array values differ:
$results_array
Array
(
[0] => Array
(
[0] => true
)
[1] => Array
(
[0] => false
)
)
UPDATE:
Both arrays will always have the same length parent arrays (but the child arrays values may vary in length).
I can't wrap my head around how to use foreach in a recursive manner to get the results array.
Any general ideas or advice?

Answer 1

You could do using == operator. Passing the first array as key-array ($k=>$arr) [since the value is another array]. Now compare the two arrays using the simple == comparison operator. You can even perform strict matching using the === operator.
<?php
$arr1=array(0=>array('A'=>'GB','B'=>'Harry','C'=>'British Army'),1=>array('A'=>'GB','B'=>'William','C'=>'Royal Air Force'));
$arr2=array(0=>array('A'=>'GB','B'=>'Harry','C'=>'British Army'),1=>array('A'=>'GB','B'=>'James','C'=>'British Army'));
foreach($arr1 as $k=>$arr)
{
$resarr[][$k]=($arr==$arr2[$k])? "true" : "false";
}
print_r($resarr);
Demo
OUTPUT :
Array
(
[0] => Array
(
[0] => true
)
[1] => Array
(
[1] => false
)
)

Answer 2

I don't know what you are trying to do with a foreach loop. Are you saying every array will have 2 child arrays or every child array will have 5 values? Regardless, I hope this helps you!
I would use some of these:
array_intersect
array_intersect_assoc
array_diff
array_diff_assoc
Code:
<?php
$array1 = [
[
'A' => 'GB',
'B' => 'Harry',
'C' => 'British Army',
'D' => 'Eton College',
'E' => 'Cressida Bonas',
],
[
'A' => 'GB',
'B' => 'William',
'C' => 'Royal Air Force',
'D' => 'Eton College',
'E' => 'Catherine Middleton',
]
];
// What Values are in common
$result1 = array_intersect_assoc($array1[0], $array1[1]);
print_r($result1);
$array2 = [
[
'A' => 'GB',
'B' => 'Harry',
'C' => 'British Army',
'D' => 'Eton College',
'E' => 'Cressida Bonas',
],
[
'A' => 'GB',
'B' => 'James',
'C' => 'British Army',
'D' => 'Millfield',
'E' => 'Unknown',
]
];
// What values are different
$result2 = array_diff_assoc($array2[0], $array2[1]);
print_r($result2);
// A Way to check numerically
$perfectMatch = 5;
$intersect = array_intersect_assoc($array1[0], $array1[1]);
$intersectCount = count($intersect);
if ($intersectCount != $perfectMatch) {
echo "<br> Not Every value matches.";
} else {
echo "<br> Perfect Match!";
}
To compare the full arrays $array1 and $array2 you can do:
<?php
// (With array code above)
$c1 = count($array1);
$c2 = count($array2);
if ($c1 != $c2) {
echo "<br>Array Children must be the same";
}
$result = [];
for ($i = 0; $i < $c1; $i++) {
$in_common = array_intersect($array1[$i], $array2[$i]);
$result[] = count($intersect);
}
print_r($result);

Answer 3

You can just use array_map(), assuming both arrays are of the same length:
$result = array_map(function($a, $b) {
return [$a == $b]; // create single element boolean array
}, $array1, $array2);
You can use either == or ===; the former (==) will yield true if both arrays have the same key and value pairs, whereas the latter (===) will only yield true if the keys of both arrays are also in the same order.

Answer 4

Some answers use the == operator; however that will not work if the arrays do not have the same key=>value matchings; Try this:
$results = array();
foreach ($array1 as $i => $subarray)
{
/* No need to proceed if subarray[i] does not exist in the second array */
if(!is_array($array2[$i]))
{
$results[$i] = false;
continue;
}
$results[$i] = (count(array_diff($array1[$i], $array2[$i])) == 0) ? true : false;
}
This solution is a bit slower than using the == comparison operator. However using the == will not work for a case like:
$array1 => array(1 => "John", 2 => "James");
$array2 => array(1 => "James", 2 => "John");
Here, the keys are not the same, but the values are duplicated. Solutions using == will return false when comparing these arrays.
$array1 == $array2 // False