Returns the value for a given key-BeJSON.com

说明

public Ds\Map::get(mixed $key, mixed $default = ?): mixed

Returns the value for a given key, or an optional default value if the key could not be found.

注意:
Keys of type object are supported. If an object implements Ds\Hashable, equality will be determined by the object's equals function. If an object does not implement Ds\Hashable, objects must be references to the same instance to be considered equal.

注意:
You can also use array syntax to access values by key, eg. $map["key"].

警告

Be careful when using array syntax. Scalar keys will be coerced to integers by the engine. For example, $map["1"] will attempt to access int(1), while $map->get("1") will correctly look up the string key.

See Arrays.

参数

key: The key to look up.
default: The optional default value, returned if the key could not be found.

返回值

The value mapped to the given key, or the default value if provided and the key could not be found in the map.

错误／异常

OutOfBoundsException if the key could not be found and a default value was not provided.

范例

示例 #1 Ds\Map::get() example


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

var_dump($map->get("a"));       // 1
var_dump($map->get("d", 10));   // 10 (default used)
?>

以上例程的输出类似于：

int(1)
int(10)

示例 #2 Ds\Map::get() example using array syntax


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

var_dump($map["a"]); // 1
?>

以上例程的输出类似于：

int(1)