array_flip
One of the ways to get intersection of two arrays is as follows:
<?php
function arrayIntersect( $primary_array, $secondary_array ) {
if ( !is_array( $primary_array ) || !is_array( $secondary_array ) ) {
return false;
}
if ( !empty( $primary_array ) ) {
foreach( $primary_array as $key => $value ) {
if ( !isset( $secondary_array[$key] ) ) {
unset( $primary_array[$key] );
} else {
if ( serialize( $secondary_array[$key] ) != serialize( $value ) ) {
unset( $primary_array[$key] );
}
}
}
return $primary_array;
} else {
return array();
}
}
?>
It would pay attention to both keys and values even if values would be arrays as well. One important note is that if value of $primary_array is yet another array, its order of key & value pairs becomes important for matching.
array_intersect_assoc
(PHP 4 >= 4.3.0, PHP 5)
array_intersect_assoc — Computes the intersection of arrays with additional index check
Description
array array_intersect_assoc
( array
$array1
, array $array2
[, array $ ...
] )
array_intersect_assoc() returns an array
containing all the values of array1
that are present in all the arguments. Note that the keys are used in
the comparison unlike in array_intersect().
Parameters
-
array1 -
The array with master values to check.
-
array2 -
An array to compare values against.
-
array -
A variable list of arrays to compare.
Return Values
Returns an associative array containing all the values in
array1 that are present in all of the arguments.
Examples
Example #1 array_intersect_assoc() example
<?php
$array1 = array("a" => "green", "b" => "brown", "c" => "blue", "red");
$array2 = array("a" => "green", "b" => "yellow", "blue", "red");
$result_array = array_intersect_assoc($array1, $array2);
print_r($result_array);
?>
The above example will output:
Array
(
[a] => green
)
In our example you see that only the pair "a" => "green" is present in both arrays and thus is returned. The value "red" is not returned because in $array1 its key is 0 while the key of "red" in $array2 is 1, and the key "b" is not returned because its values are different in each array.
The two values from the key => value pairs are considered equal only if (string) $elem1 === (string) $elem2 . In other words a strict type check is executed so the string representation must be the same.
See Also
- array_intersect() - Computes the intersection of arrays
- array_uintersect_assoc() - Computes the intersection of arrays with additional index check, compares data by a callback function
- array_intersect_uassoc() - Computes the intersection of arrays with additional index check, compares indexes by a callback function
- array_uintersect_uassoc() - Computes the intersection of arrays with additional index check, compares data and indexes by a callback functions
- array_diff() - Computes the difference of arrays
- array_diff_assoc() - Computes the difference of arrays with additional index check
add a note
User Contributed Notes
array_intersect_assoc - [6 notes]
Whitend ¶
10 months ago
vandor at progressive dot hu ¶
8 years ago
# ket tomb kulcs alapu metszetet szamitja ki, az erteken is ellenorzest vegez
#
# calculating (key base) intersection of arrays (value are checked)
# use: $result_array = array_intersect_assoc($a1, $a2, $a3,..);
#
##
# original code by [jochem at iamjochem dawt com] : array_diff_keys()
<?php
function array_intersect_assoc() {
$args = func_get_args();
$res = $args[0];
for ($i=1;$i<count($args);$i++) {
if (!is_array($args[$i])) {continue;}
foreach ($res as $key => $data) {
if ( (!array_key_exists($key, $args[$i])) || ( (isset($args[$i][$key])) && ($args[$i][$key] !== $res[$key]) ) ) {
unset($res[$key]);
}
}
}
return $res;
}
?>
<?php
$array1 = array("a"=>"green", "b"=>"brown", "c"=>"blue", "red");
$array2 = array("a"=>"green", "b"=>"yellow", "c"=>"yellow", "red");
$a = array('a'=>'green', 'b'=>'brown', 'c'=>'yellow');
$b = array('a'=>'green', 'b'=>'brown', 'c'=>'yellow', 'e'=>'yellow');
$result_array = array_intersect_assoc($a, $b, $array1, $array2);
?>
$args array will look like:
(
0 =>
(
a => green
b => brown
c => yellow
)
1 =>
(
a => green
b => brown
c => yellow
e => yellow
)
2 =>
(
a => green
b => brown
c => blue
0 => red
)
3 =>
(
a => green
b => yellow
c => yellow
0 => red
)
)
$result_array will look like:
(
a => green
)
StR: str at strgt dot cjb dot net ¶
7 years ago
To find the keys that are in 2 arrays, without caring of the values:
This is a function i needed, and it also returns the values of the first array
<?php
function array_key_intersect(&$a, &$b) {
$array = array();
while (list($key,$value) = each($a)) {
if (isset($b[$key]))
$array[$key] = $value;
}
return $array;
}
?>
nleippe at integr8ted dot com ¶
9 years ago
A combination of the two functions [array_intersect() and array_intersect_assoc()] in order to obtain the intersection of two multidimensional arrays.
<?php
function array_intersect_assoc_recursive(&$arr1, &$arr2) {
if (!is_array($arr1) || !is_array($arr2)) {
return $arr1 == $arr2; // or === for strict type
}
$commonkeys = array_intersect(array_keys($arr1), array_keys($arr2));
$ret = array();
foreach ($commonkeys as $key) {
$ret[$key] =& array_intersect_assoc_recursive($arr1[$key], $arr2[$key]);
}
return $ret;
}
?>
amoo_miki at yahoo dot com ¶
3 years ago
A method to find intersection of two or more arrays when comparison is based only on keys
array_uintersect_assoc($array1 , $array2 [, $ array... ], create_function(null, "return 0;"));
This returns an associative array containing all the keys in array1 that are present in all of the arguments.
asharm4 at ilstu dot edu ¶
7 years ago
A function to find intersection of two arrays when comparison is based on only 1 key
function array_common($array1,$array2,$compareString) {
if (!is_array($array1) || !is_array($array2)) {
return false;
}
$arrResult = array();
foreach ($array1 as $arrInsideArray1) {
foreach ($array2 as $arrInsideArray2) {
$found=false;
if ($arrInsideArray1[$compareString]==$arrInsideArray2[$compareString]) {
$found=true;
break;
}
}
if ($found) {
array_push($arrResult,$arrInsideArray1);
}
}
return $arrResult;
}