array_count_values
I've worked on array_diff_assoc_recursive() mentioned by chinello at gmail dot com and I think it might be worth mentioning here. I wrote a dozen test cases and it seems to be holding up pretty well.
<?php
// Key differences:
// * Removed redundant test;
// * Returns false bool on exact match (not zero integer);
// * Use type-precise comparison "!==" instead of loose "!=";
// * Detect when $array2 contains extraneous elements;
// * Returns "before" and "after" instead of only "before" arrays on mismatch.
function array_compare($array1, $array2) {
$diff = false;
// Left-to-right
foreach ($array1 as $key => $value) {
if (!isset($array2[$key])) {
$diff[0][$key] = $value;
} elseif (is_array($value)) {
if (!is_array($array2[$key])) {
$diff[0][$key] = $value;
$diff[1][$key] = $array2[$key];
} else {
$new = array_compare($value, $array2[$key]);
if ($new !== false) {
if (isset($new[0])) $diff[0][$key] = $new[0];
if (isset($new[1])) $diff[1][$key] = $new[1];
};
};
} elseif ($array2[$key] !== $value) {
$diff[0][$key] = $value;
$diff[1][$key] = $array2[$key];
};
};
// Right-to-left
foreach ($array2 as $key => $value) {
if (!isset($array1[$key])) {
$diff[1][$key] = $value;
};
// No direct comparsion because matching keys were compared in the
// left-to-right loop earlier, recursively.
};
return $diff;
};
?>
Note that to catch small type differences, you need to use var_dump() rather than print_r(). For example:
<?php
first = Array( 'first' => 'second', 'third' => 'fourth',
'fifth' => Array( 'oui' => 'yes', 'non' => 'no' ),
'sixth' => Array( 3, 4, 2, 1 )
);
$second = Array( 'first' => 'second', 'third' => 'fourth',
'fifth' => Array( 'oui' => 'yes', 'non' => 'no' ),
'sixth' => Array( 3, 4, '2', 1 )
);
$diff = array_compare($first, $second);
if ($diff === false) echo "MATCH\n";
else var_dump($diff);
?>
The above would immediately show that element "sixth", index 2, is int(2) in $first but string(1)"2" in $second. As per the original function, order for associative arrays does not matter, and of course it does with lists.
array_diff_assoc
(PHP 4 >= 4.3.0, PHP 5)
array_diff_assoc — Comprueba las diferencias entre matrices teniendo en cuenta los índices
Descripción
array array_diff_assoc
( array $array1
, array $array2
[, array $ ...
] )
array_diff_assoc() devuelve una matriz que contiene todos los valores de array1 que no estén presentes en ninguna de las otras matrices que se pasan como argumento. Hay que tener en cuenta que las claves de los valores se utilizan en la comparación, a diferencia de array_diff().
Example #1 Ejemplo de array_diff_assoc()
<?php
$array1 = array ("a" => "verde", "b" => "negro", "c" => "azul", "rojo");
$array2 = array ("a" => "verde", "amarillo", "rojo");
$result = array_diff_assoc ($array1, $array2);
/* El resultado es:
Array
(
[b] => negro
[c] => azul
[0] => rojo
)
*/
?>
En el ejemplo anterior se ve que el par "a" => "verde" está presente en ambas matrices y por ello no aparece en la matriz resultado. Por el contrario, el par 0 => "rojo" sí aparece en el resultado puesto que en el segundo argumento el valor "red" tiene la clave 1.
Dos valores de pares clave => valor se consideran iguales si y sólo si (string) $elem1 === (string) $elem2, es decir, cuando la representación de cadena es la misma.
Note: Hay que tener en cuenta que esta función sólo comprueba una dimensión de una matriz n-dimensional. Por supuesto, se pueden comprobar dimensiones sucesivas mediante: array_diff_assoc($array1[0], $array2[0]);.
Véase también array_diff(), array_intersect(), y array_intersect_assoc().
add a note
User Contributed Notesarray_diff_assoc
55 dot php at imars dot com
17-Mar-2009 03:09
17-Mar-2009 03:09
jrajpu10 at gmail dot com
25-Oct-2008 07:57
25-Oct-2008 07:57
array_diff_assoc can also be used to find the duplicates in an array
<?php
$arr = array('1','2','3','4','3','2','5');
$uniques = array_unique($arr);
// array_diff will not work here, array_diff_assoc works as it takes the key // in account.
$dups = array_diff_assoc($arr, $uniques);
print_r($dups);
?>
Note: The index of the $dups is not in strict sequential order as expected by C programmer.
cedric at daneel dot net
21-May-2007 01:01
21-May-2007 01:01
To diff between n-dimensional array, juste use this :
<?php
function array_diff_values($tab1, $tab2)
{
$result = array();
foreach($tab1 as $values) if(! in_array($values, $tab2)) $result[] = $values;
return $result;
}
?>
contact at pascalopitz dot com
11-Apr-2007 11:14
11-Apr-2007 11:14
The direction of the arguments does actually make a difference:
<?php
$a = array(
'x' => 'x',
'y' => 'y',
'z' => 'z',
't' => 't',
);
$b = array(
'x' => 'x',
'y' => 'y',
'z' => 'z',
't' => 't',
'g' => 'g',
);
print_r(array_diff_assoc($a, $b));
print_r(array_diff_assoc($b, $a));
?>
echoes:
Array
(
)
Array
(
[g] => g
)
chinello at gmail dot com
19-Mar-2007 06:33
19-Mar-2007 06:33
The following will recursively do an array_diff_assoc, which will calculate differences on a multi-dimensional level. This not display any notices if a key don't exist and if error_reporting is set to E_ALL:
<?php
function array_diff_assoc_recursive($array1, $array2)
{
foreach($array1 as $key => $value)
{
if(is_array($value))
{
if(!isset($array2[$key]))
{
$difference[$key] = $value;
}
elseif(!is_array($array2[$key]))
{
$difference[$key] = $value;
}
else
{
$new_diff = array_diff_assoc_recursive($value, $array2[$key]);
if($new_diff != FALSE)
{
$difference[$key] = $new_diff;
}
}
}
elseif(!isset($array2[$key]) || $array2[$key] != $value)
{
$difference[$key] = $value;
}
}
return !isset($difference) ? 0 : $difference;
}
?>
[NOTE BY danbrown AT php DOT net: This is a combination of efforts from previous notes deleted. Contributors included (Michael Johnson), (jochem AT iamjochem DAWT com), (sc1n AT yahoo DOT com), and (anders DOT carlsson AT mds DOT mdh DOT se).]
Alexander Podgorny
30-May-2006 09:30
30-May-2006 09:30
NOTE: the diff_array also removes all the duplicate values that match to the values in the second array:
<?php
$array1 = array("a","b","c","a","a");
$array2 = array("a");
$diff = array_diff($array1,$array2);
// yields: array("b","c") the duplicate "a" values are removed
?>
benjamin at moonfactory dot co dot jp
12-Jan-2005 05:56
12-Jan-2005 05:56
Hi all,
For php versions < 4.3...
<?php
/**
* array_diff_assoc for version < 4.3
**/
if (!function_exists('array_diff_assoc'))
{
function array_diff_assoc($a1, $a2)
{
foreach($a1 as $key => $value)
{
if(isset($a2[$key]))
{
if((string) $value !== (string) $a2[$key])
{
$r[$key] = $value;
}
}else
{
$r[$key] = $value;
}
}
return $r ;
}
}
?>
carl at thep dot lu dot se
09-May-2003 09:55
09-May-2003 09:55
To unset elements in an array if you know the keys but not the values, you can do:
<?php
$a = array("foo", "bar", "baz", "quux");
$b = array(1, 3); // Elements to get rid of
foreach($b as $e)
unset($a[$e]);
?>
Of course this makes most sense if $b has many elements or is dynamically generated.