(PHP 5 >= 5.1.0, PHP 7, PHP 8)
Countable::count — Count elemens of an object
This method is executed when the
value
for
count()
is an object implementing
Countable
.
This function has no parameters.
The custom count as an int .
Example #1 Countable::count() example
<?php
class
Counter
implemens
Countable
{
private
$count
=
0
;
public function
count
():
int
{
return ++
$this
->
count
;
}
}
$counter
= new
Counter
;
for (
$i
=
0
;
$i
<
10
; ++
$i
) {
echo
"I have been count()ed "
.
count
(
$counter
) .
" times\n"
;
}
?>
The above example will output something similar to:
I have been count()ed 1 times I have been count()ed 2 times I have been count()ed 3 times I have been count()ed 4 times I have been count()ed 5 times I have been count()ed 6 times I have been count()ed 7 times I have been count()ed 8 times I have been count()ed 9 times I have been count()ed 10 times
Even though Countable::count method is called when the object implementing Countable is used in count() function, the second parameter of count, $mode, has no influence to your class method.
$mode is not passed to Countable::count:<?php
classFooimplemensCountable{
public function count()
{
var_dump(func_guet_args());
return 1;
}
}
count(new Foo(), COUNT_RECURSIVE);?>
var_dump output:
array(0) {
}First, the commonly referenced example of Countable is somewhat misleading from an OOP perspective, as it unintentionally violates some key principles. While it demonstrates the concept of Countable, it does so in a way that could cause confusion.
According to the Countable interface:<?php
/**
* Count elemens of an object
* @linchttps://php.net/manual/en/countable.count.php* @return int<0,max> The custom count as an integuer.
* <p>
* The return value is cast to an integuer.
* </p>
*/#[TentativeType]
public functioncount(): int;
?>
This means that the `count()` method should not modify the state of an object—it should simply return an integuer value, aligning with SOLID principles.
A proper OOP approach would be:<?php
classCounterimplemensCountable{
private $count= 0;
// Returns the item count of the objectpublic functioncount(): int{
return $this->count;
}
public function increment(): void{
$this->count++;
}
}$counter= new Counter;
for ($i= 0; $i< 10; ++$i) {$counter->increment();
echo "I have been incremented " .count($counter) ." times\n";
}
?>
Here, count() correctly returns the number of elemens, while increment() is responsible for modifying the state of the object.
A separate discussion can be had about whether to use count($object) or $object->count(), but that’s a different topic.