array_intersect
(PHP 4 >= 4.0.1, PHP 5, PHP 7, PHP 8)
array_intersect — Вычисляет схождение массивов
Описание
Список параметров
Основной проверяемый массив
Массивы, с которыми идёт сравнение значений
Возвращаемые значения
Примеры
Пример #1 Пример использования array_intersect()
Результат выполнения данного примера:
Примечания
Смотрите также
User Contributed Notes 32 notes
A clearer example of the key preservation of this function:
?>
yields the following:
This makes it important to remember which way round you passed the arrays to the function if these keys are relied on later in the script.
array_intersect handles duplicate items in arrays differently. If there are duplicates in the first array, all matching duplicates will be returned. If there are duplicates in any of the subsequent arrays they will not be returned.
If you need to supply arbitrary number of arguments
to array_intersect() or other array function,
use following function:
Note that array_intersect and array_unique doesnt work well with multidimensional arrays.
If you have, for example,
Array
(
[ 0 ] => Array
(
[ 0 ] => John Doe
[ 1 ] => PHP Book
)
[ 1 ] => Array
(
[ 0 ] => Jack Smith
[ 1 ] => Coke
)
Array
(
[ 0 ] => Array
(
[ 0 ] => John Doe
[ 1 ] => PHP Book
)
?>
showing us who bought the same thing today and yesterday =)
Using isset to achieve this, is many times faster:
array_intersect: 4.717
array_flip+isset: 0.056
Take care of value types while using array_intersect function as there is no option for strict type check as in in_array function.
$array1 = array(true,2);
$array2 = array(1, 2, 3, 4, 5, 6);
result is :
array(2) <
[0] => bool(true)
[1] => int(2)
>
The built-in function returns wrong result when input arrays have duplicate values.
Here is a code that works correctly:
This function is able to sort an array based on another array that contains the order of occurrence. The values that are not present will be transferred into the end of the resultant.
Questa funzione permette di ordinare i valori di un array ($tosort) basandosi sui valori contenuti in un secondo array ($base), i valori non trovati verranno posizionati alla fine dell’ordinamento senza un’ordine specifico.
I used array_intersect in order to sort an array arbitrarly:
0 => ‘one’
1 => ‘four’
2 => ‘five’
3 => ‘height’
i hope this can help.
But it is not needed! See below.
Extending the posting by Terry from 07-Feb-2006 04:42:
If you want to use this function with arrays which have sometimes the same value several times, it won’t be checked if they’re existing in the second array as much as in the first.
So I delete the value in the second array, if it’s found there:
I needed to compare an array with associative keys to an array that contained some of the keys to the associative array. Basically, I just wanted to return only a few of the entries in the original array, and the keys to the entries I wanted were stored in another array. This is pretty straightforward (although complicated to explain), but I couldn’t find a good function for comparing values to keys. So I wrote this relatively straightforward one:
Array ( [first] => 2 [third] => 3 )
If you’re looking for a relatively easy way to strictly intersect keys and values recursively without array key reordering, here’s a simple recursive function:
I couldn’t get array_intersect to work with two arrays of identical objects, so I just did this:
Seems to work fine & reasonably quickly.
This is also handy for testing an array for one of a series of acceptable elements. As a simple example, if you’re expecting the query string to contain one of, say, user_id, order_id or item_id, to find out which one it is you could do this:
If you store a string of keys in a database field and want to match them to a static array of values, this is a quick way to do it without loops:
i wrote this one to get over the problem i found in getting strings intersected instead of arrays as there is no function in php.
I bench-marked some uses of array_intersect and can’t believe how slow it is. This isn’t as elaborate, but handles most cases and is much faster:
?>
You can try this out with this:
Note that array_intersect() considers the type of the array elements when it compares them.
If array_intersect() doesn’t appear to be working, check your inputs using var_dump() to make sure you’re not trying to intersect an array of integers with an array of strings.
Actually array_intersect finds the dublicate values, here is my approach which is 5 times faster than built-in function array_intersect().. Give a try..
If you wish to create intersection with arrays that are empty. Than the result of intersection is empty array.
If you wish to change this. I sugest that you do this.
It simply «ignores» empty arrays. Before loop use 1st array.
$b = array();
$b [] = 4 ;
$b [] = 5 ;
$b [] = 1 ;
$c = array();
$c [] = 1 ;
$c [] = 5 ;
$d = array();
array_intersect_assoc
(PHP 4 >= 4.3.0, PHP 5, PHP 7, PHP 8)
array_intersect_assoc — Computes the intersection of arrays with additional index check
Description
Parameters
The array with master values to check.
Arrays to compare values against.
Return Values
Returns an associative array containing all the values in array that are present in all of the arguments.
Examples
Example #1 array_intersect_assoc() example
The above example will output:
See Also
User Contributed Notes 4 notes
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:
One of the ways to get intersection of two arrays is as follows:
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
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);
[‘oranges’ => 10, ‘turtles’ => 11]
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.
array_fill_keys
(PHP 5 >= 5.2.0, PHP 7, PHP 8)
array_fill_keys — Создаёт массив и заполняет его значениями с определёнными ключами
Описание
Список параметров
Массив значений, которые будут использованы в качестве ключей. Некорректные ключи массива будут преобразованы в строку ( string ).
Возвращаемые значения
Возвращает заполненный массив
Примеры
Пример #1 Пример использования array_fill_keys()
Результат выполнения данного примера:
Смотрите также
User Contributed Notes 8 notes
now string key «1» become an integer value 1, be careful.
Some of the versions do not have this function.
I try to write it myself.
You may refer to my script below
RE: bananasims at hotmail dot com
I also needed a work around to not having a new version of PHP and wanting my own keys. bananasims code doesn’t like having an array as the second parameter.
Here’s a slightly modified version than can handle 2 arrays as inputs:
//we want these values to be keys
$arr1 = (0 => «abc», 1 => «def»);
/we want these values to be values
$arr2 = (0 => 452, 1 => 128);
returns:
abc => 452, def =>128
Scratchy’s version still doesn’t work like the definition describes. Here’s one that can take a mixed variable as the second parameter, defaulting to an empty string if it’s not specified. Don’t know if this is exactly how the function works in later versions but it’s at least a lot closer.
This works for either strings or numerics, so if we have
$arr1 = array(0 => ‘abc’, 1 => ‘def’);
$arr2 = array(0 => 452, 1 => 128);
$arr3 = array(0 => ‘foo’, 1 => ‘bar’);
array_fill_keys($arr1,$arr2)
returns: [abc] => 452, [def] => 128
array_fill_keys($arr1,0)
returns: [abc] => 0, [def] => 0
array_fill_keys($arr2,$arr3)
returns: [452] => foo, [128] => bar
array_fill_keys($arr3,’BLAH’)
returns: [foo] => BLAH, [bar] => BLAH
and array_fill_keys($arr1)
returns: [abc] =>, [def] =>
array_keys
(PHP 4, PHP 5, PHP 7, PHP 8)
array_keys — Возвращает все или некоторое подмножество ключей массива
Описание
Список параметров
Массив, содержащий возвращаемые ключи.
Если указано, будут возвращены только ключи у которых значения элементов массива совпадают с этим параметром.
Определяет использование строгой проверки на равенство (===) при поиске.
Возвращаемые значения
Примеры
Пример #1 Пример использования array_keys()
Результат выполнения данного примера:
Смотрите также
User Contributed Notes 28 notes
It’s worth noting that if you have keys that are long integer, such as ‘329462291595’, they will be considered as such on a 64bits system, but will be of type string on a 32 bits system.
?>
will return on a 64 bits system:
but on a 32 bits system:
I hope it will save someone the huge headache I had 🙂
Here’s how to get the first key, the last key, the first value or the last value of a (hash) array without explicitly copying nor altering the original array:
Since 5.4 STRICT standards dictate that you cannot wrap array_keys in a function like array_shift that attempts to reference the array.
Invalid:
echo array_shift( array_keys( array(‘a’ => ‘apple’) ) );
But Wait! Since PHP (currently) allows you to break a reference by wrapping a variable in parentheses, you can currently use:
echo array_shift( ( array_keys( array(‘a’ => ‘apple’) ) ) );
However I would expect in time the PHP team will modify the rules of parentheses.
There’s a lot of multidimensional array_keys function out there, but each of them only merges all the keys in one flat array.
Here’s a way to find all the keys from a multidimensional array while keeping the array structure. An optional MAXIMUM DEPTH parameter can be set for testing purpose in case of very large arrays.
NOTE: If the sub element isn’t an array, it will be ignore.
output:
array(
‘Player’ => array(),
‘LevelSimulation’ => array(
‘Level’ => array(
‘City’ => array()
)
),
‘User’ => array()
)
array (size=4)
0 => string ‘e’ (length=1)
1 => int 1
2 => int 2
3 => int 0
—-
expected to see:
dude dude dude
Sorry for my english.
I wrote a function to get keys of arrays recursivelly.
Here’s a function I needed to collapse an array, in my case from a database query. It takes an array that contains key-value pairs and returns an array where they are actually the key and value.
?>
Example usage (pseudo-database code):
= db_query ( ‘SELECT name, value FROM properties’ );
/* This will return an array like so:
/* Now this array looks like:
?>
I found this handy for using with json_encode and am using it for my project http://squidby.com
This function will print all the keys of a multidimensional array in html tables.
It will help to debug when you don?t have control of depths.
An alternative to RQuadling at GMail dot com’s array_remove() function:
The position of an element.
One can apply array_keys twice to get the position of an element from its key. (This is the reverse of the function by cristianDOTzuddas.) E.g., the following may output «yes, we have bananas at position 0».
Hope this helps someone.
# array_keys() also return the key if it’s boolean but the boolean will return as 1 or 0. It will return empty if get NULL value as key. Consider the following array:
Array
(
[ 0 ] => first_index
[ 1 ] => 1
[ 2 ] => 0
[ 3 ] => 4
[ 4 ] => 08
[ 5 ] => 8
[ 6 ] =>
)
This function will extract keys from a multidimensional array
Array
(
[color] => Array
(
[1stcolor] => blue
[2ndcolor] => red
[3rdcolor] => green
)
[size] => Array
(
[0] => small
[1] => medium
[2] => large
)
Array
(
[0] => color
[1] => 1stcolor
[2] => 2ndcolor
[3] => 3rdcolor
[4] => size
[5] => 0
[6] => 1
[7] => 2
)
All the cool notes are gone from the site.
Here’s an example of how to get all the variables passed to your program using the method on this page. This prints them out so you can see what you are doing.
Simple ways to prefixing arrays;
[1] => Array
(
[product_id] => 2
[product_name] => Bar
)
I was looking for a function that deletes either integer keys or string keys (needed for my caching).
As I didn’t find a function I came up with my own solution.
I didn’t find the propiest function to post to so I will post it here, hope you find it useful.
?>
You can of course define constants to have a nicer look, I have chosen these: EXTR_INT = 1; EXTR_STRING = 2
EXTR_INT will return an array where keys are only integer while
EXTR_STRING will return an array where keys are only string
A needed a function to find the keys which contain part of a string, not equalling a string.
array_key_exists
(PHP 4 >= 4.0.7, PHP 5, PHP 7, PHP 8)
array_key_exists — Проверяет, присутствует ли в массиве указанный ключ или индекс
Описание
Список параметров
Массив с проверяемыми ключами.
Возвращаемые значения
Возвращает true в случае успешного выполнения или false в случае возникновения ошибки.
array_key_exists() ищет ключи только на первом уровне массива. Внутренние ключи в многомерных массивах найдены не будут.
Примеры
Пример #1 Пример использования array_key_exists()
Пример #2 array_key_exists() и isset()
Примечания
Смотрите также
User Contributed Notes 38 notes
If you want to take the performance advantage of isset() while keeping the NULL element correctly detected, use this:
Benchmark (100000 runs):
array_key_exists() : 205 ms
is_set() : 35ms
isset() || array_key_exists() : 48ms
Note:
The code for this check is very fast, so you shouldn’t warp the code into a single function like below, because the overhead of calling a function dominates the overall performance.
function array_check(. )
<
return (isset(..) || array_key_exists(. ))
>
You’ll notice several notes on this page stating that isset() is significantly faster than array_key_exists(). This may be true except for one small hitch. isset() will return false for arrays keys that have there value set to NULL, which is therefore not entirely accurate.
= array();
$foo [ ‘bar’ ] = NULL ;
Beware that if the array passed to array_key_exists is NULL, the return value will also be NULL.
This is undocumented behaviour, moreover the documentation (and return typehint) suggest that the array_key_exists function only returns boolean value. But that’s not the case.
The way array_key_exists handles null, float, boolean, and ‘integer-representing string’ keys is inconsistent in itself and, in the case of bool and float, with the way these are converted when used as array offset.
array (
» => 1,
0 => 2,
1 => 3,
4 => 4,
’08’ => 5,
8 => 6,
)
null is a key.
false is not a key.
true is not a key.
4.6 is not a key.
«08» is a key.
«8» is a key.
Well, and you get this warning three times (on the bools and the float, but not on the null):
Warning: array_key_exists() [function.array-key-exists]: The first argument should be either a string or an integer in /var/www/php/test.php on line 6
The argument of array_key_exists() vs. isset() came up in the workplace today, so I conducted a little benchmark to see which is faster:
?>
On Windows, the output is similar to
array_key_exists(): 0.504 [82.895%] seconds
isset(): 0.104 [17.105%] seconds
On Mac or Linux, isset() is faster but only by a factor of approximately 1.5.
I’ve got a new take on the multi key function I would like to share.
Very simple case-insensitive array_key_exists:
bool (in_array(strtolower($needle), array_map(‘strtolower’, array_keys($haystack))))
array_key_exists doesn’t work with objects implementing ArrayAccess interface. It also ignores possible __get() method in such objects, despite the fact it accepts object as a second parameter. It works only with ‘real’ properties.
Here is an example with array_key_exists switching between content-types :
I took hours for me to debug, and I finally recognized that,
Or you will get no reply.
Rudi’s multidimensional array_key_exists function was not working for me, so i built one that is.
Enjoy.
Here is a little function for case sensitivity to elaborate on what was said by MarkL from ##php (Freenode) and mmanning at mdanderson dot org from this page:
Also, I’ve been running into issues with escaping for Regex, so I decided to give something like this a shot:
Regarding performance differences between isset() and array_key_exists(), the differences may be there, but the function are not always interchangable.
A little function which take an array as keys
Here’s a function to return a reference to the first array element that has a given key. The code works for multidimensional arrays:
I created this function that uses array key exist to compare a form and a table to see if something has changed.
This can be very helpfull if you need to update a table record from a form but you do not want to display all table fields.
/// it works like array_key_exists that can go deeper
$cidade = array(
‘redonda’ => array(
‘curta’ => ‘o seu filme’
),
‘quadrada’ => array(
‘longa’ => array(
‘azul’ => array(‘logo’,2,’mais’,2,’são’,4),
‘amarela’ => array(‘então’,3,’vezes’,2,’são’,6),
‘verde’ => array(‘senão’,100,’dividido por’,2,’é’,50)
),
‘extravagante’ => array(
‘vermelha’ => ‘chama atenção’,
‘vinho’ => ‘cor de uva’,
‘ocre’ => 1255
),
‘comprida’ => array(
‘amarela’ => ‘brasilia dos mamonas’,
‘branca’ => ‘bandeira da paz’,
‘preta e branca’ => ‘peças do xadrez’
)
),
‘oval’ => array(
‘conde’ => ‘lobo’
),
‘plana’ => array(
‘curta’ => array(
‘azul’ => array(‘e’,2,’mais’,2,’são’,4),
‘amarela’ => array(‘sim’,3,’vezes’,2,’são’,6),
‘verde’ => array(‘verdade’,100,’dividido por’,2,’é’,50)
)
)
);
/// if the tree you search for exists, it will print out ‘true’
Further research on this has turned up that the performance problems are a known, confirmed bug in PHP 5.1.x, and have been fixed in PHP builds after September 2006. You can find the bug report here: http://bugs.php.net/bug.php?id=38812
However, just because it’s a fixed bug doesn’t really change the conclusion. If you’re writing a script and there’s any chance it could be used on a PHP 5.1.x server, you should still avoid this function and use isset() or some other kind of test if you want it to run efficiently.
I saw some examples above for array_keys_exist() or functions to see if multiple keys exist in a given array and return false if any of them don’t.
Here is a simpler way to do this: