I have an associative array that I might need to access numerically (ie get the 5th key's value).
$data = array(
'one' => 'something',
'two' => 'else',
'three' => 'completely'
) ;
I need to be able to do:
$data['one']
and
$data[0]
to get the same value, 'something'.
My initial thought is to create a class wrapper that implements ArrayAccess with offsetGet() having code to see if the key is numeric and act accordingly, using array_values:
class MixedArray implements ArrayAccess {
protected $_array = array();
public function __construct($data) {
$this->_array = $data;
}
public function offsetExists($offset) {
return isset($this->_array[$offset]);
}
public function offsetGet($offset) {
if (is_numeric($offset) || !isset($this->_array[$offset])) {
$values = array_values($this->_array) ;
if (!isset($values[$offset])) {
return false ;
}
return $values[$offset] ;
}
return $this->_array[$offset];
}
public function offsetSet($offset, $value) {
return $this->_array[$offset] = $value;
}
public function offsetUnset($offset) {
unset($this->_array[$offset]);
}
}
I am wondering if there isn't any built in way in PHP to do this. I'd much rather use native functions, but so far I haven't seen anything that does this.
Any ideas?
Thanks,
Fanis
how about this
$data = array(
'one' => 'something',
'two' => 'else',
'three' => 'completely'
) ;
then
$keys = array_keys($data);
Then
$key = $keys[$index_you_want];
Then
echo $data[$key];
There isn't a built-in way to do this.
If it's a one-off thing you could use something like:
$array = array_merge($array, array_values($array));
This won't update as you add new items to the array though.
i noticed you mentioned it is a readonly database result set
if you are using mysql then you could do something like this
$result = mysql_query($sql);
$data = mysql_fetch_array($result);
mysql_fetch_array returns an array with both associative and numeric keys
http://nz.php.net/manual/en/function.mysql-fetch-array.php
Sometimes it's easier to check if you have an associative key or an index with is_int()
if(is_int($key))
return current(array_slice($data, $key, 1));
else
return $data[$key];
Related
I would like to use the list() statement in combination with an object.
$tuple = new Tuple();
// ..
list ($guestbook, $entry, $author) = $tuple;
This would work if $tuple was an array with three elements. But its an object.
Is there any way without using a method of Tuple (returning that kind of array) like implementing a fancy native interface I yet don't know?
You can implement the interface ArrayAccess to do so:
class Tuple implements ArrayAccess {
private $arr;
public function __construct($arr) {
$this->arr = $arr;
}
public function offsetExists($offset) {
return array_key_exists($offset, $this->arr);
}
public function offsetGet($offset) {
return $this->arr[$offset];
}
public function offsetSet($offset, $value) {
return $this->arr[$offset] = $value;
}
public function offsetUnset($offset) {
unset($this->arr[$offset]);
}
}
$tuple = new Tuple([1, 2, 3]);
list($am, $stram, $gram) = $tuple;
echo $am;
echo $stram;
echo $gram;
// outputs: 123
See this previous post:
Convert PHP object to associative array
I am assuming (I haven't tested it) you could then do:
$tuple = new Tuple();
list ($guestbook, $entry, $author) = (array) $tuple;
You can do this:
$tumple = new Tumple();
$properties = get_object_vars($tumple);// ["guestbook" => "Feel", "entry" => "Good", "author" => "Inc"];
When writing controllers for Symfony 2, I often need to pass quite a few variables to the template like return array('param1' => $param1, 'anotherBigParam' => $anotherBigParam, 'yetAnotherParam' => $yetAnotherParam);
With many parameters this ends up really long and ugly, so I thought about creating a helper function for it:
public function indexAction()
{
$param1 = 'fee';
$anotherBigParam = 'foe';
$yetAnotherParam = 'fum';
return $this->vars('param1', 'anotherBigParam', 'yetAnotherParam');
}
private function vars() {
$arr = array();
foreach(func_get_args() as $arg) {
$arr[$arg] = $$arg;
}
return $arr;
}
Is there some kind of drawback or risk from doing this? Does PHP or Symfony 2 already provide a better or cleaner way to achieve the same result?
There is a native way of doing it: compact
$one = 'ONE';
$two = 'TWO';
$a = compact( 'one', 'two' );
print_r( $a );
/*
Array
(
[one] => ONE
[two] => TWO
)
*/
You're looking for compact.
public function indexAction()
{
$param1 = 'fee';
$anotherBigParam = 'foe';
$yetAnotherParam = 'fum';
return compact('param1', 'anotherBigParam', 'yetAnotherParam');
}
Suppose I have:
class A{
public $one;
public $two;
}
and an array with values:
array('one' => 234, 'two' => 2)
is there a way to have an instance of A filled with the right values from the array automatically?
You need to write yourself a function for that. PHP has get_object_varsDocs but no set counterpart:
function set_object_vars($object, array $vars) {
$has = get_object_vars($object);
foreach ($has as $name => $oldValue) {
$object->$name = isset($vars[$name]) ? $vars[$name] : NULL;
}
}
Usage:
$a = new A();
$vars = array('one' => 234, 'two' => 2);
set_object_vars($a, $vars);
If you want to allow for bulk-setting of attributes, you can also store them as a property. It allows you to encapsulate within the class a little better.
class A{
protected $attributes = array();
function setAttributes($attributes){
$this->attributes = $attributes;
}
public function __get($key){
return $this->attributes[$key];
}
}
#hakre version is quite good, but dangerous (suppose an id or password is in thoses props).
I would change the default behavior to that:
function set_object_vars($object, array $vars) {
$has = get_object_vars($object);
foreach ($has as $name => $oldValue) {
array_key_exists($name, $vars) ? $object->$name =$vars[$name] : NULL;
}
}
here, the previous properties that are not in the $vars array are not affected.
and if you want to set a prop to null on purpose, you can.
Yes there is.
You could use a pass thru method.
For example:
class A {
public $one, $tow;
function __construct($values) {
$this->one = $values['one'] ?: null;
$this->two = $values['two'] ?: null;
}
}
$a = new A(array('one' => 234, 'two' => 2));
Is there any method like the array_unique for objects? I have a bunch of arrays with 'Role' objects that I merge, and then I want to take out the duplicates :)
array_unique works with an array of objects using SORT_REGULAR:
class MyClass {
public $prop;
}
$foo = new MyClass();
$foo->prop = 'test1';
$bar = $foo;
$bam = new MyClass();
$bam->prop = 'test2';
$test = array($foo, $bar, $bam);
print_r(array_unique($test, SORT_REGULAR));
Will print:
Array (
[0] => MyClass Object
(
[prop] => test1
)
[2] => MyClass Object
(
[prop] => test2
)
)
See it in action here: http://3v4l.org/VvonH#v529
Warning: it will use the "==" comparison, not the strict comparison ("===").
So if you want to remove duplicates inside an array of objects, beware that it will compare each object properties, not compare object identity (instance).
Well, array_unique() compares the string value of the elements:
Note: Two elements are considered equal if and only if (string) $elem1 === (string) $elem2 i.e. when the string representation is the same, the first element will be used.
So make sure to implement the __toString() method in your class and that it outputs the same value for equal roles, e.g.
class Role {
private $name;
//.....
public function __toString() {
return $this->name;
}
}
This would consider two roles as equal if they have the same name.
This answer uses in_array() since the nature of comparing objects in PHP 5 allows us to do so. Making use of this object comparison behaviour requires that the array only contain objects, but that appears to be the case here.
$merged = array_merge($arr, $arr2);
$final = array();
foreach ($merged as $current) {
if ( ! in_array($current, $final)) {
$final[] = $current;
}
}
var_dump($final);
Here is a way to remove duplicated objects in an array:
<?php
// Here is the array that you want to clean of duplicate elements.
$array = getLotsOfObjects();
// Create a temporary array that will not contain any duplicate elements
$new = array();
// Loop through all elements. serialize() is a string that will contain all properties
// of the object and thus two objects with the same contents will have the same
// serialized string. When a new element is added to the $new array that has the same
// serialized value as the current one, then the old value will be overridden.
foreach($array as $value) {
$new[serialize($value)] = $value;
}
// Now $array contains all objects just once with their serialized version as string.
// We don't care about the serialized version and just extract the values.
$array = array_values($new);
You can also serialize first:
$unique = array_map( 'unserialize', array_unique( array_map( 'serialize', $array ) ) );
As of PHP 5.2.9 you can just use optional sort_flag SORT_REGULAR:
$unique = array_unique( $array, SORT_REGULAR );
You can also use they array_filter function, if you want to filter objects based on a specific attribute:
//filter duplicate objects
$collection = array_filter($collection, function($obj)
{
static $idList = array();
if(in_array($obj->getId(),$idList)) {
return false;
}
$idList []= $obj->getId();
return true;
});
From here: http://php.net/manual/en/function.array-unique.php#75307
This one would work with objects and arrays also.
<?php
function my_array_unique($array, $keep_key_assoc = false)
{
$duplicate_keys = array();
$tmp = array();
foreach ($array as $key=>$val)
{
// convert objects to arrays, in_array() does not support objects
if (is_object($val))
$val = (array)$val;
if (!in_array($val, $tmp))
$tmp[] = $val;
else
$duplicate_keys[] = $key;
}
foreach ($duplicate_keys as $key)
unset($array[$key]);
return $keep_key_assoc ? $array : array_values($array);
}
?>
If you have an indexed array of objects, and you want to remove duplicates by comparing a specific property in each object, a function like the remove_duplicate_models() one below can be used.
class Car {
private $model;
public function __construct( $model ) {
$this->model = $model;
}
public function get_model() {
return $this->model;
}
}
$cars = [
new Car('Mustang'),
new Car('F-150'),
new Car('Mustang'),
new Car('Taurus'),
];
function remove_duplicate_models( $cars ) {
$models = array_map( function( $car ) {
return $car->get_model();
}, $cars );
$unique_models = array_unique( $models );
return array_values( array_intersect_key( $cars, $unique_models ) );
}
print_r( remove_duplicate_models( $cars ) );
The result is:
Array
(
[0] => Car Object
(
[model:Car:private] => Mustang
)
[1] => Car Object
(
[model:Car:private] => F-150
)
[2] => Car Object
(
[model:Car:private] => Taurus
)
)
sane and fast way if you need to filter duplicated instances (i.e. "===" comparison) out of array and:
you are sure what array holds only objects
you dont need keys preserved
is:
//sample data
$o1 = new stdClass;
$o2 = new stdClass;
$arr = [$o1,$o1,$o2];
//algorithm
$unique = [];
foreach($arr as $o){
$unique[spl_object_hash($o)]=$o;
}
$unique = array_values($unique);//optional - use if you want integer keys on output
This is very simple solution:
$ids = array();
foreach ($relate->posts as $key => $value) {
if (!empty($ids[$value->ID])) { unset($relate->posts[$key]); }
else{ $ids[$value->ID] = 1; }
}
You can also make the array unique using a callback function (e.g. if you want to compare a property of the object or whatever method).
This is the generic function I use for this purpose:
/**
* Remove duplicate elements from an array by comparison callback.
*
* #param array $array : An array to eliminate duplicates by callback
* #param callable $callback : Callback accepting an array element returning the value to compare.
* #param bool $preserveKeys : Add true if the keys should be perserved (note that if duplicates eliminated the first key is used).
* #return array: An array unique by the given callback
*/
function unique(array $array, callable $callback, bool $preserveKeys = false): array
{
$unique = array_intersect_key($array, array_unique(array_map($callback, $array)));
return ($preserveKeys) ? $unique : array_values($unique);
}
Sample usage:
$myUniqueArray = unique($arrayToFilter,
static function (ExamQuestion $examQuestion) {
return $examQuestion->getId();
}
);
array_unique version for strict (===) comparison, preserving keys:
function array_unique_strict(array $array): array {
$result = [];
foreach ($array as $key => $item) {
if (!in_array($item, $result, true)) {
$result[$key] = $item;
}
}
return $result;
}
Usage:
class Foo {}
$foo1 = new Foo();
$foo2 = new Foo();
array_unique_strict( ['a' => $foo1, 'b' => $foo1, 'c' => $foo2] ); // ['a' => $foo1, 'c' => $foo2]
array_unique works by casting the elements to a string and doing a comparison. Unless your objects uniquely cast to strings, then they won't work with array_unique.
Instead, implement a stateful comparison function for your objects and use array_filter to throw out things the function has already seen.
This is my way of comparing objects with simple properties, and at the same time receiving a unique collection:
class Role {
private $name;
public function __construct($name) {
$this->name = $name;
}
public function getName() {
return $this->name;
}
}
$roles = [
new Role('foo'),
new Role('bar'),
new Role('foo'),
new Role('bar'),
new Role('foo'),
new Role('bar'),
];
$roles = array_map(function (Role $role) {
return ['key' => $role->getName(), 'val' => $role];
}, $roles);
$roles = array_column($roles, 'val', 'key');
var_dump($roles);
Will output:
array (size=2)
'foo' =>
object(Role)[1165]
private 'name' => string 'foo' (length=3)
'bar' =>
object(Role)[1166]
private 'name' => string 'bar' (length=3)
If you have array of objects and you want to filter this collection to remove all duplicates you can use array_filter with anonymous function:
$myArrayOfObjects = $myCustomService->getArrayOfObjects();
// This is temporary array
$tmp = [];
$arrayWithoutDuplicates = array_filter($myArrayOfObjects, function ($object) use (&$tmp) {
if (!in_array($object->getUniqueValue(), $tmp)) {
$tmp[] = $object->getUniqueValue();
return true;
}
return false;
});
Important: Remember that you must pass $tmp array as reference to you filter callback function otherwise it will not work
Is there a version of the PHP array class where all the elements must be distinct like, for instance, sets in Python?
Nope. You could fake it by using an associative array where the keys are the elements in the "set" and the values are ignored.
Here's a first-draft of an idea that could eventually work for what you want.
<?php
class DistinctArray implements IteratorAggregate, Countable, ArrayAccess
{
protected $store = array();
public function __construct(array $initialValues)
{
foreach ($initialValues as $key => $value) {
$this[$key] = $value;
}
}
final public function offsetSet( $offset, $value )
{
if (in_array($value, $this->store, true)) {
throw new DomainException('Values must be unique!');
}
if (null === $offset) {
array_push($this->store, $value);
} else {
$this->store[$offset] = $value;
}
}
final public function offsetGet($offset)
{
return $this->store[$offset];
}
final public function offsetExists($offset)
{
return array_key_exists($offset, $this->store);
}
final public function offsetUnset($offset)
{
unset( $this->store[$offset] );
}
final public function count()
{
return count($this->store);
}
final public function getIterator()
{
return new ArrayIterator($this->store);
}
}
$test = new DistinctArray(array(
'test' => 1,
'foo' => 2,
'bar' => 3,
'baz' => '1',
8 => 4,
));
try {
$test[] = 5;
$test[] = 6;
$test['dupe'] = 1;
}
catch (DomainException $e) {
echo "Oops! ", $e->getMessage(), "<hr>";
}
foreach ($test as $value) {
echo $value, '<br>';
}
You can use a special class, or array_unique to filter the duplicates.
An array is an array, and for the most part yo can put anything into it. All keys must be unique. If you want to go and add a function that strips out duplicate values, that is very possible by simply doing a array_unique statement
For objects that are not integers and strings: SplObjectStorage
The SplObjectStorage class provides a map from objects to data or, by ignoring data, an object set.
You can use this Set class. You can install with pecl
sudo pecl install ds
there is also a polyfill version available if u have no root access
composer require php-ds/php-ds
In a basic way you could try array_unique(), maybe this could help to avoid duplicates in your array.
You cannot use array_unique.
If you use int and string values, array_unique uses a string-representation for comparison, so array [1,'1','2'] will result in [1,'2'].
You can trick
Array Key index are unique.
So you can store unique val as string keys, like a python set.
$liste , is just a bad exemple for simulate datas.
$liste = ['1','1','2','3','4'];
$uniq = [];
for ($liste as elem) {
$uniq[$elem] = 1;
}
$uniq = array_keys($uniq);
// Or use directly
for ($uniq as $uniqVal => $null) {
echo $uniqVal;
}