Ds\Map::count()函数是PHP中的内置函数, 用于计算Map中存在的元素数。它也指Map的大小。
语法如下：
int public Ds\Map::count()参数：此函数不接受任何参数。
返回值：此函数返回Map中存在的元素数。
下面的程序说明了Ds\Map::count()PHP中的功能：
程序1：
<?php
// PHP program to illustrate the count()
// function of Ds\map
// Creating a Map
$map = new \Ds\Map([
"1" => "Geeks" , "2" => "for" , "3" => "Geeks"
]);
// Display the map elements
print_r( $map );
echo "Number of elements present in map: " ;
print_r( $map -> count ());
?>输出如下：
Ds\Map Object
(
[0] => Ds\Pair Object
(
[key] => 1
[value] => Geeks
)
[1] => Ds\Pair Object
(
[key] => 2
[value] => for
)
[2] => Ds\Pair Object
(
[key] => 3
[value] => Geeks
)
)
Number of elements present in map: 3程式2：
<?php
// PHP program to illustrate the count()
// function of Ds\map
// Creating a Map
$map = new \Ds\Map([ "1" => "10" , "2" => "20" , "3" => 30, "4" => 40]);
// Print map elements
print_r( $map );
echo "Number of elements present in map: " ;
print_r( $map -> count ());
echo "\n" ;
// Creating another Map
$map = new \Ds\Map([1 => "Welcome" , 2 => "to" , 3 => "lsbin" ]);
// Print map elements
print_r( $map );
echo "Number of elements present in map: " ;
print_r( $map -> count ());
?>输出如下：
Ds\Map Object
(
[0] => Ds\Pair Object
(
[key] => 1
[value] => 10
)
[1] => Ds\Pair Object
(
[key] => 2
[value] => 20
)
[2] => Ds\Pair Object
(
[key] => 3
[value] => 30
)
[3] => Ds\Pair Object
(
[key] => 4
[value] => 40
)
)
Number of elements present in map: 4
Ds\Map Object
(
[0] => Ds\Pair Object
(
[key] => 1
[value] => Welcome
)
[1] => Ds\Pair Object
(
[key] => 2
[value] => to
)
[2] => Ds\Pair Object
(
[key] => 3
[value] => lsbin
)
)
Number of elements present in map: 3参考： https://www.php.net/manual/en/ds-map.count.php
