array keys php,php array_keys与array_search的简单使用

函数说明

array_keys():返回数组中所有的键名。

array_search():在数组中搜索给定的值，如果成功则返回相应的键名。

//根据一个key返回关联数组中的另一个key,并且不使用foreach

// function array_key_relative(array $array, string $current_key, int $offset)

function array_key_relative($array, $current_key, $offset = 1) {

// create key map

$keys = array_keys($array);

// find current key

$current_key_index = array_search($current_key, $keys);

// return desired offset, if in array, or false if not

if(isset($keys[$current_key_index + $offset])) {

return $keys[$current_key_index + $offset];

}

return false;

}

//Usage example:

$test_array = array(

"apple" => "Red, shiny fruit",

"orange" => "Orange, dull, juicy fruit",

"pear" => "Usually green and odd-shaped fruit",

"banana" => "Long yellow fruit that monkeys like to eat",

"cantelope" => "Larger than a grapefruit",

"grapefruit" => "Kind of sour"

);

echo array_key_relative($test_array, "apple", 2); // outputs "pear"

echo array_key_relative($test_array, "orange", -1); // outputs "apple" */

$next_key = array_key_relative($test_array, "banana", 1); // Get the key after banana (cantelope)

echo $test_array[$next_key]; // outputs "Larger than a grapefruit"

?>