PHP | Ds\Map count()函数

Ds\Map::count()函数是PHP中的一个内置函数，用于计算 Map 中存在的元素数量。它还提到了地图的大小。

句法：

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 中存在的元素数量。

下面的程序说明了PHP中的Ds\Map::count()函数：

方案一：

 "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：

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

方案二：

 "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 => "GeeksforGeeks"]); 
  
// Print map elements
print_r($map); 
  
echo "Number of elements present in map: ";
print_r($map->count());
  
?> 

输出：

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] => GeeksforGeeks
        )

)
Number of elements present in map: 3

参考： https://www. PHP.net/manual/en/ds-map.count。 PHP