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    array_intersect_assoc

    (PHP 4 >= 4.3.0, PHP 5, PHP 7, PHP 8)

    array_intersect_assoc — 带索引检查计算数组的交集

    说明

    array_intersect_assoc(array $array, array ...$arrays): array

    array_intersect_assoc() 返回一个数组，该数组包含了所有在 array 和其它参数数组中同时存在的值。注意和 array_intersect() 不同的是，键名也用于比较。

    参数

    array

    要检查的数组，作为主值。

    arrays

    要被对比的数组。

    返回值

    返回一个关联数组，该数组包含了所有在 array 和其它参数数组中同时存在的值。

    更新日志

    版本 说明
    8.0.0 现在可以仅使用一个参数调用此函数。以前，至少需要两个参数。

    示例

    示例 #1 array_intersect_assoc() 例子

    <?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);
    ?>

    以上示例会输出：

     
Array
(
    [a] => green
)

    上面例子中可以看到，只有键值对 "a" => "green" 在两个数组中都存在，从而被返回。 值 "red" 没有被返回，是因为在 $array1 中它的键名是 0 而在 $array2 中 "red" 的键名是 1，键 "b" 没有返回的原因是，它的值和其他数组不同。

    仅在 (string) $elem1 === (string) $elem2 时， key => value 才被认为是相等的。 也就是说使用了严格的类型检查，字符串的表达形式必须相同。

    参见

    ＋add a note

    User Contributed Notes 4 notes

    up
    6
    Whitend
    11 years ago
    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.
    up
    4
    vandor at progressive dot hu
    18 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
    )
    up
    -5
    StR: str at strgt dot cjb dot net
    18 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;
    }
    ?>
    up
    -7
    Jim Yaghi
    6 years ago
    Remember, null values will be interpreted as, "key does not exist." eg,

    $a = ['apples' => 1, 'oranges' => 2, 'turtles' => null, 'bananas'=>4];
    $b = ['apples'=>10, 'turtles' => 11, 'eggs'=>12];
    $c = array_intersect_assoc($b,$a);

    You might have expected $c to contain:

    ['oranges' => 10, 'turtles' => 11]

    In fact, 'turtles' has a null value in the $a array, therefore the $c array contains only:

    ['oranges' => 10]

    Something to keep in mind if using array_intersect_assoc to filter valid entries, eg in a mySQL insertion pre-processing or nerdy API that doesn't like extra params.
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