PHP如何使用Ds\Map count()函数（代码实例） _map

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

【PHP如何使用Ds\Map count()函数（代码实例）】参考： https://www.php.net/manual/en/ds-map.count.php