PHP如何使用Ds\Map count()函数?代码实例

2021年3月31日17:56:28 发表评论 64 次浏览

Ds\Map::count()函数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


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