Php key object keys

Php key object keys

key — Выбирает ключ из массива

Описание

key() возвращает индекс текущего элемента массива.

Список параметров

Возвращаемые значения

Функция key() просто возвращает ключ того элемента массива, на который в данный момент указывает внутренний указатель массива. Она не сдвигает указатель ни в каком направлении. Если внутренний указатель указывает вне границ массива или массив пуст, key() возвратит null .

Список изменений

Версия	Описание
8.1.0	Вызов функции в объекте ( object ) объявлен устаревшим. Либо сначала преобразуйте объект ( object ) в массив ( array ) с помощью функции get_mangled_object_vars() , либо используйте методы, предоставляемые классом, реализующим интерфейс Iterator , например, ArrayIterator .
7.4.0	Экземпляры классов SPL теперь обрабатываются как пустые объекты, не имеющие свойств, вместо вызова метода Iterator с тем же именем, что и эта функция.

Примеры

Пример #1 Пример использования key()

$array = array(
‘fruit1’ => ‘apple’ ,
‘fruit2’ => ‘orange’ ,
‘fruit3’ => ‘grape’ ,
‘fruit4’ => ‘apple’ ,
‘fruit5’ => ‘apple’ );

// этот цикл выведет все ключи ассоциативного массива,
// значения которых равны «apple»
while ( $fruit_name = current ( $array )) if ( $fruit_name == ‘apple’ ) echo key ( $array ), «\n» ;
>
next ( $array );
>
?>

Результат выполнения данного примера:

Смотрите также

• current() — Возвращает текущий элемент массива
• next() — Перемещает указатель массива вперёд на один элемент
• array_key_first() — Получает первый ключ массива
• foreach

User Contributed Notes 5 notes

Note that using key($array) in a foreach loop may have unexpected results.

When requiring the key inside a foreach loop, you should use:
foreach($array as $key => $value)

I was incorrectly using:
foreach( $array as $value )
$mykey = key ( $array );
>
?>

and experiencing errors (the pointer of the array is already moved to the next item, so instead of getting the key for $value, you will get the key to the next value in the array)

CORRECT:
foreach( $array as $key => $value )
$mykey = $key ;
>

A noob error , but felt it might help someone else out there .

Suppose if the array values are in numbers and numbers contains `0` then the loop will be terminated. To overcome this you can user like this

while ( $fruit_name = current ( $array ))

echo key ( $array ). ‘
‘ ;
next ( $array );
>

// the way will be break loop when arra(‘2’=>0) because its value is ‘0’, while(0) will terminate the loop

// correct approach
while ( ( $fruit_name = current ( $array )) !== FALSE )

echo key ( $array ). ‘
‘ ;
next ( $array );
>
//this will work properly
?>

Needed to get the index of the max/highest value in an assoc array.
max() only returned the value, no index, so I did this instead.

reset ( $x ); // optional.
arsort ( $x );
$key_of_max = key ( $x ); // returns the index.
?>

(Editor note: Or just use the array_keys function)

Make as simple as possible but not simpler like this one 🙂

In addition to FatBat’s response, if you’d like to find out the highest key in an array (assoc or not) but don’t want to arsort() it, take a look at this:

$arr = [ ‘3’ => 14 , ‘1’ => 15 , ‘4’ => 92 , ’15’ => 65 ];

$key_of_max = array_search ( max ( $arr ) , $arr );

• Функции для работы с массивами
  • array_​change_​key_​case
  • array_​chunk
  • array_​column
  • array_​combine
  • array_​count_​values
  • array_​diff_​assoc
  • array_​diff_​key
  • array_​diff_​uassoc
  • array_​diff_​ukey
  • array_​diff
  • array_​fill_​keys
  • array_​fill
  • array_​filter
  • array_​flip
  • array_​intersect_​assoc
  • array_​intersect_​key
  • array_​intersect_​uassoc
  • array_​intersect_​ukey
  • array_​intersect
  • array_​is_​list
  • array_​key_​exists
  • array_​key_​first
  • array_​key_​last
  • array_​keys
  • array_​map
  • array_​merge_​recursive
  • array_​merge
  • array_​multisort
  • array_​pad
  • array_​pop
  • array_​product
  • array_​push
  • array_​rand
  • array_​reduce
  • array_​replace_​recursive
  • array_​replace
  • array_​reverse
  • array_​search
  • array_​shift
  • array_​slice
  • array_​splice
  • array_​sum
  • array_​udiff_​assoc
  • array_​udiff_​uassoc
  • array_​udiff
  • array_​uintersect_​assoc
  • array_​uintersect_​uassoc
  • array_​uintersect
  • array_​unique
  • array_​unshift
  • array_​values
  • array_​walk_​recursive
  • array_​walk
  • array
  • arsort
  • asort
  • compact
  • count
  • current
  • end
  • extract
  • in_​array
  • key_​exists
  • key
  • krsort
  • ksort
  • list
  • natcasesort
  • natsort
  • next
  • pos
  • prev
  • range
  • reset
  • rsort
  • shuffle
  • sizeof
  • sort
  • uasort
  • uksort
  • usort
  • each

  Источник

  Retrieve object keys with their corresponding values in PHP

  One way to find the interesting object in constant time is by organizing your collection into a dictionary data structure such as a hash table. Alternatively, you can search your collection which takes linear time. Another solution is to reorganize your array and create an associative array column.

  PHP: get a single key from object

  I possess an object with a sole value and key, however, I am unaware of the key used to access it. What is the most effective method to acquire the key without having to enumerate the entire object?

  If your sole intention is to retrieve the value, the key, which is also known as the property name, is not required.

  $value = current((array)$object); 

  To obtain the name of the property, follow this suggestion.

  $array = array("foo" => "bar"); $keys = array_keys($array); echo $keys[0]; // Output: foo 

  Check out the documentation for the «array_keys» function on «php.net» website.

  It is possible to transform the object into an array using the following syntax:

  If an array contains only one value, the key for that value must be retrieved.

  If you prefer, you have the option of combining both actions into a single line. Alternatively, as you mentioned in your question, you could list out the object to achieve the same result.

  To retrieve the actual worth as opposed to the identifier, follow these steps:

  PHP: get a single key from object, I have an object with a single key and its value. But I don’t know the key to access it. Are you looking to do an array_search? – Brandon Horsley. Aug 5, 2010 at 3:26. 2. I have just a single json object converted to php like <"foo":3>and I need to take both, key name and value. – Pablo. Aug 5, 2010 at 3:29. Usage example$key = key((array)$object);Feedback

  PHP Get keys with values from object

  To parse my XML file in PHP, I am utilizing simplexml_load_string() . To enhance the readability, I have also json_encode() d my object. You can see an example of a German school in this pastebin link: http://pastebin.com/Hk8YCssR (Example Representation Plan ). My objective is to create two objects, one containing all actions and the other containing all keys of the «head». Though I attempted to loop through these keys, I was unable to retrieve the value of a key’s key.

  To obtain the value «5/2» in this instance.

  Although I am unable to provide the precise code, I am currently documenting my actions in a sketch.

  $value = current((array)$xml); echo $value; foreach ($xml as $key) < // echo $key[]; >

  Thank you for taking the time to read this.

  $sv_infch=get_object_vars($xml[0]->info); foreach($sv_infch as $key => $value) < print "$key =>$value\n"; echo " => "; print_r($sv_infch); > 

  Oop — Accessing Object with Key as Number PHP, Connect and share knowledge within a single location that is structured and easy to search. Accessing Object with Key as Number PHP [duplicate] Ask Question Asked 9 years, I need to modify some values inside the object. I’m not sure where or how it’s created. But I will learn more as I dig deeper.

  PHP get object with specific key value [duplicate]

  How can I retrieve metafield objects in PHP that only have the namespace «global»?

  $response = json_decode($response, true); $filtered['metafields'] = array_filter($response['metafields'], function ($item) < return $item['namespace'] === 'global'; >); var_dump($filtered); array(1) < ["metafields"]=>array(2) < [0]=>array(2) < ["id"]=>int(30007223558) ["namespace"]=> string(6) "global" > [2]=> array(2) < ["id"]=>int(154644565) ["namespace"]=> string(6) "global" > > > 

  PHP array_search() Function, Returns the key of a value if it is found in the array, and FALSE otherwise. If the value is found in the array more than once, the first matching key is returned. This function returns NULL if invalid parameters are passed to it (this applies to all PHP functions as of 5.3.0). As of PHP 4.2.0, this function returns FALSE on failure …

  PHP — Find an object by key in an array of objects, update its value

  I possess a collection of entities and intend to modify a specific entity’s property.

  $objs = [ ['value' => 2, 'key' => 'a'], ['value' => 3, 'key' => 'b'] , ]; 

  To assign the value 5 to the object with the key ‘a’, let’s say.

  Is there a more expedient method to accomplish this task rather than scanning the array for the key repeatedly?

  The reason for not being able to utilize an associative array is being discussed, and it is due to the fact that the array is derived from a JSON value.

  If my JSON object is this:

  Retaining the order of objects is necessary, but it cannot be guaranteed.

  Thus, in order to sort each object using usort() , an index is required for each object. Therefore, the JSON should have an index for each object.

  Applying usort() is limited to arrays and cannot be used on objects. Therefore, my JSON format must be modified accordingly.

  This leads us back to the initial inquiry.

  With the help of array_column() , you can extract all the values from the arrays that have the index key . After that, applying array_search() would enable you to detect the initial occurrence of the value a . The outcome would only be the first index where the value is found, allowing you to effortlessly replace it using the obtained index.

  $keys = array_column($objs, 'key'); $index = array_search('a', $keys); if ($index !== false)

  It would be advisable to consider restructuring your array in the following manner:

  $objs = [ 'a' => ['value'=>2, 'key'=>'a'], 'b' => ['value'=>3, 'key'=>'b'] ]; 

  if( array_key_exists( 'a', $objs ))

  Initially, I set it up that way. However, I require an index value to be present in the objects for the purpose of using the usort() function on the primary array. The reason behind this is that the array originates from JSON, which does not maintain the original sequence.

  Next, generate an array identified as index .

  // When fill `$objs` array $objs = []; $arrIndex = []; $idx = 0; foreach( $json as $item ) < $arrIndex [ $item ['key']] = $idx; $objs [$idx ++] = $item; >// And your task: if( array_key_exists( 'a', $arrIndex ))

  By using the array column, it is possible to make the array associative, allowing for the direct assignment of values.

  $objs = [ ['value'=>2, 'key'=>'a'], ['value'=>3, 'key'=>'b'] ]; $objs = array_column($objs, null, "key"); $objs['a']['value'] = 5; 

  Other than the method of iterating over the array to find the key, is there a faster or more efficient way to accomplish this task?

  Regardless of the situation, iteration always comes with a cost that must be paid.

  One way to locate an interesting object in your collection is by conducting a linear search, while another option is to create a dictionary such as a hash table, which would enable you to locate the object in constant time.

  PHP get object with specific key value, Connect and share knowledge within a single location that is structured and easy to search. PHP get object with specific key value [duplicate] Ask Question Asked 5 years, 4 months ago. Modified 5 years, 4 months ago. Viewed 3k …

  Источник