array ( 0 => 'index.php', 1 => 'PHP Manual', ), 'head' => array ( 0 => 'UTF-8', 1 => 'zh', ), 'this' => array ( 0 => 'ds-map.isempty.php', 1 => 'Ds\\Map::isEmpty', 2 => 'Returns whether the map is empty', ), 'up' => array ( 0 => 'class.ds-map.php', 1 => 'Ds\\Map', ), 'prev' => array ( 0 => 'ds-map.intersect.php', 1 => 'Ds\\Map::intersect', ), 'next' => array ( 0 => 'ds-map.jsonserialize.php', 1 => 'Ds\\Map::jsonSerialize', ), 'alternatives' => array ( ), 'source' => array ( 'lang' => 'en', 'path' => 'reference/ds/ds/map/isempty.xml', ), 'history' => array ( ), ); $setup["toc"] = $TOC; $setup["toc_deprecated"] = $TOC_DEPRECATED; $setup["parents"] = $PARENTS; manual_setup($setup); contributors($setup); ?>

Ds\Map::isEmpty

(PECL ds >= 1.0.0)

Ds\Map::isEmpty — Returns whether the map is empty

说明

public Ds\Map::isEmpty(): bool

Returns whether the map is empty.

参数

此函数没有参数。

返回值

Returns true if the map is empty, false otherwise.

示例

示例 #1 Ds\Map::isEmpty() example

<?php
$a = new \Ds\Map(["a" => 1, "b" => 2, "c" => 3]);
$b = new \Ds\Map();

var_dump($a->isEmpty());
var_dump($b->isEmpty());
?>

以上示例的输出类似于：

bool(false)
bool(true)